Learning prefixes will help you understand many unfamiliar words.

A-/An-*

Ab-

Agri-

Ante-

Auto-

Ambi-

Amphi-

Anti-

Bi-

Bio-

Co-

Con-/Com-

Counter-

De-

Dia-

Dis-/Dys-

Down-

Ex-

Extra-

Geo-

Hyper-

Hypo-

Il-/In-/Im-/Ir-

Inter-

Macro-

Mega-

Meta-

Micro-

Mid-

Mis-

Mono-

Non-

Omni-

Out-

Over-

Para-

Post-

Pre-

Pro-

Re-

Semi-

Sub-

Super-

Tele-

Trans-

Ultra-

Un-**

Uni-

Under-

Zoo-

not

away, from

farming

before

self

both, around, round about

of both kinds

against, opposed to

two

life

jointly, partner

with

contrary, opposing

reverse, change

through, across

not, reverse, opposite of

lower, reduce

out, previous

outside of, beyond

Earth

extreme

under

not, without

between

large

very large, important

after, behind; changed; beyond

small

middle

badly, wrongly

one

not

all, every

more, better

too much

beside, beyond

after (time)

before (time), early

in favor of

again

half

under, below

above, beyond

at/over a distance

across, beyond

extremely, beyond (place)

opposite of, not

one

less than, beneath

animal

atypical, asocial

abnormal, absent

agriculture, agro-economic zone

antecedent, antebellum

automatic, autopilot

ambiguous, ambidextrous

amphibian, amphibious

antidote, antivirus, antisocial

biannual, biped

biology, biodegradable

co-pilot, coexist, co-author

community, cooperate

counterfeit, counterculture

devalue, deactivate, debug

diameter, dialogue

disappear, dysfunctional

download, downsize

exit, external, eccentric, ex-friend

extraterrestrial, extracurricular

geology, geography

hyperactive, hyperextend

hypodermic, hypoxia

impossible, insecure, illicit, infrequent

international, intersect

Makro, macroeconomics

megalithic. megalomaniac

metabolic, metaphysics

microscope, microscopic

mid-November, midterm

mistreat, miscalculate

monocyte, monograph

non-combatant, non-countable

omnipotent, omnidirectional

outdistance, outnumber

overheat, overwork

paragraph, paranormal

post-war, post-natal

prepare, preview, preheat, precede

pro-abortion, pro-communist

review, recycle, renew

semicircular, semi-conscious

submarine, sub-standard, sub par

superable, supersonic, Superman

telescope, telepathy, telephone

transportation, transfer

ultraistic, ultrashort, ultramontane

unfriendly, undo, unknown, uneaten

uniform, universe

undercook, undercoat, undersized

zoolatry, zoological

*Note the words awake, asleep, anew, and arise. The a- in these words does not mean not.

**Un- is often used with adjectives.