Prefixes & Suffixes

What the ASVAB is actually testing

Word Knowledge is 15 questions on the CAT-ASVAB. You'll see words you've studied, and words you haven't. Prefixes and suffixes are how you get partial credit on unfamiliar words. The test isn't checking whether you memorized every vocab list. It's checking whether you can reason about language under time pressure.

A word like insubordinate might never have appeared in your prep materials. But if you know in- means "not" and sub- means "under," you've cut the guessing down dramatically.

The prefixes worth memorizing first

Negative / reversal:

• un-, unable, unfit, unkempt
• dis-, displace, disloyal, disrupt
• mis-, misjudge, misconduct, mislead
• mal-, malfunction, malicious, malnourished
• non-, noncombatant, nonessential, nonfatal
• anti-, antidote, antiaircraft, antisocial

Time and position:

• pre-, predict, precaution, premature
• post-, postwar, postpone, posterior
• sub-, submarine, subordinate, substandard
• inter-, intercept, intervene, international
• trans-, transport, transfer, transcend

Degree and size:

• over-, overestimate, overpowered
• hyper-, hyperactive, hypersensitive
• micro-, microscopic, microcosm

Suffixes that signal meaning

-ous (full of): hazardous, conspicuous, strenuous
-ful (having): resourceful, forceful, dreadful
-less (without): reckless, careless, relentless
-able / -ible (capable of): capable, flexible, compatible
-tion / -sion (act or state): mission, operation, condition
-ist (one who): strategist, specialist, antagonist
-ify / -fy (to make): fortify, clarify, magnify

Dissect before you guess

Take noncombatant: non- (not) + combat + -ant (one who does). A noncombatant = one who does not combat, a civilian or medical personnel in a military context.

Take subversive: sub- (under/against) + vers (to turn) + -ive (tending to). Subversive = tending to undermine or turn against authority.

Two or three parts, decoded separately, give you the full meaning, even if you've never seen the word before.

What trips people up

The in- ambiguity. In- can mean "not" (inactive, incomplete) or "into/within" (insert, incorporate). The meaning depends on the root. Don't assume every in- word is a negative.

Stopping after the prefix. You identify mal- and think "bad." That's a start, not an answer. Malevolent, malodorous, and malicious are all "bad", but they mean different things. The root narrows it.

Spelling vs. meaning on -able/-ible. Both mean "capable of." The distinction is spelling only. Don't waste time on the difference, use it to confirm the meaning, not to choose between two answers.

Practice move

Prefixes and suffixes work best when you've drilled them until they're automatic. If you still have to consciously recall what mal- means mid-question, you're burning time the test doesn't give you. Work through the practice set until you're splitting words on sight, then apply it to full Word Knowledge question sets.