Latin PREFIXES with look alikes and common mix-ups

AB-, A-, ABS-

away from, from

AD-, AC-

to, toward

CIRCUM

around

DE

down, away, reversal

EX-, E-, EF-

out, out of

EXTRA-, EXTRO-

outside, beyond

IN-, IM-, [EN-], [EM-] (directional)

into, in, on

INFRA

below, beneath

INTER

between, among

INTRA-, INTRO-

within, inside

OB

against, toward, in the way

PER

through, thoroughly

SUB-, SUS-, SUC-

under, below

SUPER-, [SUR-]

above, over

TRANS-, TRAN-, TRA-

across, through, beyond

ULTRA

beyond, excessively

RETRO

backward

ANTE

before

POST

after

PRO

forward, for, in favor of

RE-, RED- (before vowel)

back again

CON-, COM-, CO-

with, together

AMBI

both, around

CONTRA-, CONTRO-, COUNTER-

against

DIS-, DI-, DIF-

apart, not, away

IN-, IM-, [IG-before n] (negative)

not, without

NON

not

SE-, SED (before vowels)

apart, aside, without

Negative IN- (“not”)

inactive, impossible, ignoble (IG- before n)

Directional IN- (“into”)

inject, immerse, enclose (EN-), empower (EM-)

VERT- and VERS-, —> vertere (“to turn”)

Convert VS. conversion

GRAD- and GRESS-, —> gradi (“to step”)

graduate VS. progress

PEND- and PENS-, —>pendere ( “to hang, weigh”)

suspend VS. pension

overlapping meaning, different latin words

FIRM- (strong, firm) vs. FORT (strong, brave)

near synonyms, distinct bases

SACR- (sacred, holy) vs. SANCT- (holy, inviolable)

both about absence, but not interchangeable in derivatives

NIHIL- (nothing) vs. NUL(L)- (none, not any)

true synonyms, only usage in specific words tells them apart (predict vs antecedent)

PRE- (before) vs. ANTE- (before)