Many students are aware that you need a good vocabulary to do well on the ACT, but they're often not sure just how their vocabulary will be tested. Gone are the days where you needed to learn the definitions of dozens of obscure words, but a good vocabulary is still key to excelling on the ACT. To help you out, we've compiled a list of 163 key ACT vocabulary words to know. We also explain how vocab is tested on the ACT, the types of questions you'll see, and the best way to study ACT vocab words.
Standardized tests in general have shifted away from emphasizing vocabulary, and the ACT is part of that trend. Whereas before it was common to have questions that directly asked you about the definition of a word, there is now much more of a focus on understanding words in context, rather than being able to rattle off dozens of word definitions strictly from memory.
However, a strong vocabulary will absolutely help you on the ACT, especially if you're aiming for a high or perfect score. Even if fewer questions ask directly about word definitions, an expansive vocabulary will help you read through passages more quickly and have a more solid understanding of the topics they're discussing.
ACT vocabulary questions are now primarily focused on testing your ability to understand and define words in context. You may see them in either the Reading or English sections.
Some of the words you'll be asked about may be unusual, but most or all of them should be known to you. You'll no longer be expected to know the definitions of obscure words that you rarely hear in normal life. Question 19, below, is an example of an ACT English question you might see. This example comes from an official ACT practice test.
To answer question 19 correctly, you'd need to know the definitions of cumbersome, thorny, strenuous, and gawky. You've likely heard or read each of these words, although you may not be rock solid on every definition. You also need to get context from the passage to answer the question. If you read through the entire passage, you'll learn that the Navajo code was much easier to use than previous codes, so you know the best answer for question 19 will be a word that contrasts with "simple" or "easy." Cumbersome, defined as "unwieldy" or "burdensome" is the best choice, so the correct answer is A.
Here's the type of vocab question you might see in ACT Reading:
Humor is a word you know, but all four answer choices could be correct depending on the context. You'd need to read the passage and understand which option fits the context best to answer the question.
As you can see, the vocab words tested on the ACT don't often go beyond a medium-level difficulty, but you still need to have a solid vocabulary and understand how to define words in specific contexts.
Below is a table of the 163 top ACT vocabulary words to study and know. For each word, we include the definition and an example sentence that contains the word so you have more context for it.
To compile this list, we read through every publicly available official ACT practice exam and looked at both the Reading and Writing sections (and not just the questions but the answer choices and passages, too). We also used our own knowledge of the types of words you can expect to see most often on standardized tests.
Though you don’t need to memorize every word in this chart, familiarizing yourself with most of them will help you better identify the tones of passages and make you more efficient at interpreting and answering questions correctly on the ACT.
