Many students are confused about ACT vocabulary and how it differs from the words tested on the SAT. Unfortunately, most free resources about ACT vocabulary are just SAT vocabulary with a different title. But in this article, we break down exactly how the ACT tests vocabulary, the words it tests most often, and tips to approach vocabulary in the Reading and Writing sections. Plus, we give you a list of our Top 15 ACT words and a free study sheet of our Top 150 ACT Words!
Background to ACT Vocab
(Stick with me here, this is relevant to how ACT tests vocab).
Our modern idea of "vocabulary" in terms of academic testing comes from the College Board's almost 100-year-old approach to it. The first SAT, in 1926, included thirty three of this kind of rudimentary fill-in-the-blank vocabulary question:
(See the end of this post for the answers to this and the following questions.)
The above approach treats language much like algebra: the goal is to find the correct "value" to go in a specific spot. And the above fill-in-the-blank questions are also why, for as long as most of us can remember, kids have prepared for tests by memorizing definitions. This is because, for the above kind of test, it's easy to score high just by cramming a hundred definitions into your brain. But the College Board—and the US education system—soon learned that knowing the definition of a word is not the same as knowing how to use it effectively.
How Vocabulary is Tested Today
So today's tests are more complex than the one above from 1926; they try to test your understanding not only of the textbook definition of the word, but your understanding of its place in the language as well. For example, the dictionary definition of engender is "to cause." But a student who only knows the definition might think engenders belongs in the following sentence: "The harsh professor ___ the sensitive student to cry."
But engender actually means something between "encourage" and "cause"; it would be weird to say the professor encouraged the student to cry, wouldn't it? It would be better to say that the harshness itself engendered something. And, secondly, engender can only be followed by a noun; it would be correct to say "The professor's harsh tone _engenders_ a tense classroom atmosphere."
So it turns out that a word's use in the context of language is just as important as its definition. And most big tests have caught onto this, and while the SAT still has a fill-in-the-blank reading section, the sentences in those questions provide (and require students to understand) some context for the answer choices.
But the ACT takes an even subtler approach to testing vocabulary: they include it where knowing the word is crucial to understanding or answering the question, usually without testing it directly. In other words, the vocabulary words on the ACT are usually surrounded by a decent number of hints as to their meanings. These hints are also known as context clues, and we'll talk about those next.
The ACT Loves Context
As we discussed earlier, knowing definitions of words isn't as good a measure of language mastery as is the skill of choosing the best word for a specific context. In other words, it's less about the words themselves and more about how they fit with the words around them. The ACT really takes this to heart and rewards students who know how to use context clues. By contrast, the SAT specifically tries to isolate words so that context gives limited help. Here's an SAT example:
In the question above, the only clue we get to the meaning of the blank is stringent, which is another tough vocabulary word! To illustrate the difference between this approach and the ACT's, here's an ACT question that (indirectly) targets vocabulary:
The difficult words in the question above are sound and intact, which both mean undamaged, but this is only part of the question. The word total seems like it fits into the list of words, but when we insert it into the sentence, it reads "the feather is total," which is clearly wrong. So we need to know that sound and intact mean something like "whole," but there's other information (context) that helps us answer the question.
Here's another interesting ACT example. The highlighted words are the ones that you need to know to get the question right with 100% certainty.
So, on the above tougher ACT English question, we need to know that emphatic means "expressing something forcibly and clearly" in order to choose correctly between the options. Only one choice (asserts) is even close to that definition, but it's also a tough word for many students. However, if we know emphatic, then we know that hints, supposes and probably says aren't strong enough. Again, in this ACT question, we have some leeway with our vocabulary skills.
What Kinds of Words the ACT Tests
So now we know that the ACT has a very specific, context-focused approach to testing vocabulary words. But the words the ACT chooses to test are also different from the ones the SAT tests. Here's how.
The ACT Only Tests Medium-Level Vocabulary, but Tests It in Detail
When you look at the Top 15 ACT Words at the bottom of this article, you may already know many of the words. That's great! But make sure you really do know what they mean—look them up and read them in a few different sentences to be sure. Because while the ACT doesn't test you on SAT-style vocabulary like abstemious, crepuscular, or blunderbuss, it does test you on the nuances of its easier words, like adhere, cumbersome, and diffuse. Many of these nuances include multiple meanings, which we'll delve into now.
The ACT Loves Words with Multiple Meanings
The ACT likes to test the secondary (less well known) or academic meanings of words. Let's look at a few examples from real ACTs: what do the words determined and critical mean to you?
You probably thought of the most common definitions of these words: determined is an adjective that means "persistent," and critical is an adjective that means "disapproving."
But both of these words also have secondary, more academic meanings. Determined, for example, is also the past tense of the verb determine, which means "to establish something exactly." For example: "In the 16th century, Nicolaus Copernicus determined that the Earth revolves around the Sun." Determine, used in this way, is one of the most common vocabulary words on the ACT.
Critical, by contrast, is always an adjective (most words ending in "-al" are), but it still has multiple meanings. While the more popular meaning of critical, "disapproving," describes a person, the academic meaning describes an analysis or explanation of something. For example: "The scholar's critical analysis of Macbeth shows that Macbeth's greed is the main cause of the play's events."
Metaphorical Secondary Meanings
One trick you can use on the ACT (but less so on the SAT) is to think of unknown words metaphorically.
For example, the word cumbersome technically means "large or heavy and therefore difficult to carry or use." But it's actually more often used to mean "slow or complicated and therefore inefficient." Now let's look at an ACT Reading example in which we can apply this strategy.
Let's say that we think the answer to the question above is F, but that we don't know what self-absorption means. We certainly know that "absorb" means to soak up or take in, and we know what "self" means. If we think of "absorb" in a metaphorical way—soaking in one's emotions or thoughts, rather than absorbing liquid with a paper towel—we might be able to guess that "self-absorption" means being absorbed by one's self, not focusing on anything external.
This tactic applies to many of the multiple-meaning words tested on the ACT.
The ACT Loves Idioms
Another way the ACT tries to test language skills (that the SAT does not) is idioms (phrases that mean something different than what the actual words mean). For example, "bite the bullet" is an English idiom that means to do something that's difficult to do. It doesn't have anything to do with biting or bullets. Here are a few idioms from recent ACTs:
- hush-hush: secret
- under wraps: secret
- streak past: go past quickly
- came about: happened
- in the midst: during
- sheds light on: reveals, explains
- ill at ease: uncomfortable (mentally, not physically)
- dwell on: focus on for longer than necessary
- against the clock: under time pressure
- stumbled upon: discovered by accident
It's difficult to study idioms, and there are thousands of them in English. The ACT only tests idioms that are very widely used, so an easy way to improve your idiom knowledge is to read, read, read—anything that's not for kids. And if you read a phrase that doesn't make sense, ask an adult—idioms can be difficult to look up reliably on the internet.
The ACT Includes Science Vocabulary
Lots of people freak out about ACT Science, but it's really quite straightforward—if you're familiar with science. There are difficult topics and vocabulary, like heritable traits and conductivity, but the test explains all of these very specifically.
The more general and vague science terms, however, you have to already know or work around. One thing that can make ACT Science less scary (especially if you haven't taken chemistry or biology recently) is to make sure you know some basic scientific ACT vocabulary words.
The vocabulary list attached to this article includes almost 40 science vocabulary words for just this purpose. It can also be useful to read articles in scientific publications, like Popular Science or the science section of the New York Times.
The New 2016 SAT Vocabulary Looks More Like ACT Vocabulary
The College Board has promised to make its test more relevant to college success, which means omitting (getting rid of) a bunch of obscure (not well known) words like lachrymose (tearful, sad) and ushering in more college-level words that are more frequently used in academic texts. In the Top 15 ACT Vocab Words below, note that each can be used broadly to discuss various academic topics.
PrepScholar's Top 15 ACT Vocab Words
The ACT uses a lot of the same vocabulary words over and over. Unsurprisingly, they relate strongly to literary and scientific topics, and have variations (italicized and in parentheses below) that are also important for the test. You may notice that many of them have multiple meanings; the extended Top 150 ACT Words list tells you which is most likely to appear on the ACT.
These are the words you absolutely must know!
- analyze: examine in detail, typically for purposes of explanation and interpretation (analysis, analytical)
- write or create
- constitute, make up (composition, composed of)
- correlate: have a mutual relationship or connection (corollary, correlated)
- expressing adverse or disapproving comments or judgments
- expressing or involving an analysis of the merits and faults of a work of literature, music, or art
- involving the objective analysis and evaluation of an issue in order to form a judgement
- (of a situation or problem) having the potential to become disastrous; at a point of crisis
- cause (something) to occur in a particular way; be the decisive factor in
- ascertain or establish exactly, typically as a result of research or calculation
- recognize or ascertain what makes (someone or something) different
- (differentiate between) identify differences between (two or more things or people)
- make (someone or something) appear different or distinct
- make or become different in the process of growth or development
- occupy, attract, or involve (someone's interest or attention)
- (engage someone in) cause someone to become involved in (a conversation or discussion)
- (engage in) participate or become involved in
- emerge: become apparent, important, or prominent
- evolve: develop gradually, especially from a simple to a more complex form
- infer: deduce or conclude (information) from evidence and reasoning rather than from explicit statements (inference)
- omit: leave out or exclude (someone or something), either intentionally or forgetfully
- come before (something) in time
- come before in order or position (preceding)
- redundant: not or no longer needed or useful
- (of a surface or body) throw back (heat, light, or sound) without absorbing it
- (of a mirror or shiny surface) show an image of
- embody or represent (something) in a faithful or appropriate way
- (reflect well/badly on) bring about a good or bad impression of: the incident reflects badly on the operating practices of the airlines.
- (reflect on/upon) think deeply or carefully about
- relevant: closely connected or appropriate to the matter at hand (antonym: irrelevant)
Answers to the questions in this article:
(28) is economics
(29) is cellulose
(30) is homeopathy
(5) is A, circumscribed
(63) is C, total
(73) is D, asserts
(28) is F
Make sure you download our exclusive list of the Top 150 ACT Vocab Words you must know. This is a list collected through thorough research into previous ACT tests. If you know these words, you'll have a big leg up on the actual test.
Read our guide on the best way to memorize vocab words. Even though the linked article talks about SAT vocab, the method can be applied to any and all vocab words.
Wondering about whether you should take the ACT or the SAT to get into college? Read our detailed breakdown of whether the ACT is easier than the SAT.
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Laura has over a decade of teaching experience at leading universities and scored a perfect score on the SAT.