Top 20 ACT Vocabulary Words

Worried about ACT vocabulary? Worry no more! We’ve collected the top 20 ACT vocabulary words you should know—along with their definitions and parts of speech—in one place for your studying ease. Without further ado…

Top 20 ACT Vocabulary Words*

	Word	Part of Speech	Definition(s)
1	adhere	verb	to stick to a surface or substance [or] to follow a practice or belief
2	anticipate	verb	to regard as probable [or] to expect or predict
3	characteristic	adjective	a special quality of a person, thing, or group
4	compose	verb	to write or create [or] to constitute or make up (e.g. water is composed of hydrogen and oxygen)
5	critical	adjective	expressing criticism or disapproval [or] relating to the careful judgements of critics (usually about books, art, movies, etc.) [or] using careful judgment about the good and bad parts of something
6	determine	verb	to make an official decision, based on evidence or facts [or] to be the cause or reason for something [or] to learn something by getting information
7	differentiate	verb	to recognize what makes someone or something different [or] to make someone or something appear different [or] to become different in the process of development
8	engage	verb	to occupy or attract someone’s interest or attention [or] to participate in something
9	glaring	adjective	giving or reflecting a strong light [or] very obvious or conspicuous
10	hypothesis	noun	a supposition or proposed explanation based on limited evidence, used as a starting point for further investigation
11	imminent	adjective	about to happen
12	inevitable	adjective	unavoidable [or] when used as a noun, a situation that is unavoidable (e.g. “I don’t want to be here when the inevitable occurs”
13	intuition	noun	the ability to understand something before using conscious reasoning [or] something that one knows before thinking about it; a “gut feeling.”
14	justify	verb	to show or prove to be right [or] to be a good reason for doing something
15	omit	verb	to intentionally leave something or someone out [or] to leave something undone
16	precede	verb	to come before in time, order, or position [or] to go in front of or ahead of
17	redundant	adjective	no longer useful, superfluous, extra [or] able to be left out without sacrificing meaning or usefulness
18	relevant	adjective	appropriate to the matter at hand
19	trivial	adjective	of small value or importance [or] a person only concerned with unimportant things
20	uniform	adjective	not changing in form or character, or similar in form or character to other things [or] a piece of clothing that is part of a uniform

*As I mentioned in the Top Tips post, the ACT will more commonly test secondary definitions of common words than esoteric or abstruse vocabulary. Bear in mind that the second and third definitions of the words on this list are important, too! If you need more vocab practice, check out Magoosh ACT Prep.