Common Prefixes and Suffixes

Knowing the meaning of common prefixes and suffixes will help you figure out the definition of many familiar and unfamiliar words on the ACT exam.

What Exactly Are Prefixes and Suffixes?
Prefixes and suffixes are attached to base words to add information and meaning. A prefix is an attachment that comes before a base word or stem.

A suffix is an attachment that comes after the existing base word or stem. A stem is the main part of a word—the part that prefixes or suffixes are attached to—but might not actually be a full word by itself.
The word repayment, for example, is made up of the prefix re- (which means again), the stem pay, and the suffix -ment (which means action or process). So with an understanding of suffix, prefix, and stems, you could figure out that the meaning of repayment is the process of paying money back.

Common Prefixes
The following are some examples of prefixes you might encounter when studying ACT vocabulary words, along with their meanings.

a-, ab-, an- (apart or without)
ad- (toward or near)
ante- (before)
anti- (against)
auto- (self)
bi- (two)
bio- (life)
circum- (around)
co-, com-, con- (with or together)
de- (away or off)
di-, dis- (not or apart)
dys- (bad or problematic)
em-, en- (restrict or cause)
equi- (equal)
ex- (former)
extra-, exo- (outside of)
fore- (in front of or before)
hy per- (over)
hypo- (under)
geo- (earth)
im-, in- (not)
inter-(between)
micro- (tiny)
mis- (wrong)
mono- (one)
multi- (many)
neo- (new)
non- (not)
ob-, oc-, of-, op- (against, on, over, or toward)
omni- (all)
pan- (all)
para- (beyond)
peri- (around or about)
poly- (many)
post- (after)
pre- (before)
pro- (favoring or for)
re- (again)
retro- (backward)
semi- (half)
sub- (under or below)
super- (exceeding or above)
therm-, thermo- (heat)
trans- (across)
tri- (three)
un- (not)

Common Suffixes

-able, -ible (capable or worthy of)
-acy (state or quality)
-age (condition)
-al (act or process of, or pertaining to)
-ance, -ence (state or quality)
-ary (related to)
-ate (become)
-dom (place or state of being)
-en (make or become)
-er, -or (one who)
-esque (like or reminiscent of)
-gram, -graph (written or drawn)
-hood (class)
-ic, -ical (pertaining to)
-iou, -ous (characterized by)
-ish (having the quality of)
-ive (having the nature of)
-less (without)
-log, -logue (speech)
-logy (the study of)
-oid (resembles)
-ory, -tory (relating to)
-ous (possessing)
-phile (strong love for)
-phobe, -phobia (fear of)
-ship (position held)
-y (characterized by)

Derivational Suffixes
There are suffixes that change the meaning of the base word or stem. These are called derivational suffixes, and some common examples are:

-able, -ible (capable of being)
-ation, -sion, -tion (state of being)
-ful (notable for)
-fy (make or become)
-ify (make or become)
-ily
-ise, -ize (become)
-ism (belief or doctrine)
-ist (one who)
-ity, -ty (having the quality of)
-ment (condition or result of)
-ness (state of being)

Derivational suffixes can combine with each other, too, but the spelling may change (as in predictability, which is predict combined with -able and -ity).

Exercise 1
Each word below contains a prefix. Using what you learned, choose the best available definition.
1. microcosm a. to make something larger b. a sign of fear c. a smaller system which is representative of a larger one d. a vast expanse of land
2. foreshadow a. to darken b. to suggest something in advance c. to follow d. to retaliate
3. engender a. to bring into existence; to cause b. knowledge c. to promise to marry d. to grow
4. commingle a. to bring forward b. to mix or blend c. a quick movement d. to soften
5. extraordinary a. from the past b. exceptional or unusual c. from above d. large

Exercise 2
Each word below contains a suffix. Using what you learned, choose the best available definition.
1. historical a. dry b. extremely funny c. something that belongs to a man d. relating to what happened in the past
2. provenance a. place or source of origin b. a gift c. the act of being proper or correct d. happiness
3. fiefdom a. a type of instrument b. unhappiness c. a domain controlled by a dominant person or lord d. a small area
4. travelogue a. a vacation b. a language c. confrontation d. the journal or documentation of a trip
5. humanoid a. resembling or having the characteristics of a human b. false or fake c. a very young person d. an alien

Exercise 3
Each word below contains a prefix and a suffix or derivational suffix. Using what you learned, choose the best available definition.
1. decentralize a. to cause to be more populated b. in the very middle of an area c. to move downward d. to move away from an established main point
2. monograph a. a work of writing on a single subject b. a diverse group c. a drawing made with many colors d. a signature
3. apprehension a. to climb b. fearful expectation c. a course that comes before a meal d. the state of being angry
4. nullify a. to take apart b. to make invalid c. to bring together d. to make liquid
5. approbation a. a decision b. restriction c. concern d. official approval

Answers:
Exercise 1
1. c. a smaller system which is representative of a larger one
2. b. to suggest something in advance
3. a. to bring into existence; to cause
4. b. to mix or blend
5. b. exceptional or unusual

Exercise 2
1. d. relating to what happened in the past
2. a. place or source of origin
3. c. domain controlled by a dominant person or lord
4. d. the journal or documentation of a trip
5. a. resembling or having the characteristics of a human

Exercise 3
1. d. move away from an established main point
2. a. work of writing on a single subject
3. b. fearful expectation
4. b. make invalid
5. d. official approval