A prefix changes a word's meaning from the front. Know 20 or so, and thousands of words become easier to guess.
Look-alikes to keep apart
| Prefix | Means | Example |
|---|---|---|
| ante- | before | antebellum |
| anti- | against | antibiotic |
| inter- | between | international |
| intra- | within | intravenous |
| sub- | under | submarine |
| super- | over | supervise |
The tricky one: in-
In- has two meanings: not (inaccurate) and in/into (inhale). That's why inflammable means the same as flammable, and why safety signs now prefer “flammable.”
Without: a- vs im-
- amoral: without morals, not thinking about right and wrong at all.
- immoral: knowing what's right and doing wrong anyway.
Latin and Greek twins
English often has two prefixes for the same idea, one from each language: mono-/uni- (one), poly-/multi- (many), hemi-/semi- (half). Greek ones show up in science words (hemisphere), Latin ones in everyday words (semicircle).
Put it together
trans- (across) + port (carry) = transport. inter- (between) + rupt (break) = interrupt. circum- (around) + spect (look) = circumspect, looking around before you act.
Independent study material, not affiliated with College Board or ETS.