Grammar: Affixes & Roots

Grammar in EAP

Word Formation

Affixes and roots

Adding affixes to existing words (the base or root) to form new words is common in academic English. Prefixes are added to the front of the base (likedislike), whereas suffixes are added to the end of the base (activeright arrowactivate). Prefixes usually do not change the class of the base word, but suffixes usually do change the class of the word.

The most common prefixes used to form new verbs in academic English are: re-, dis-, over-, un-, mis-, out-. The most common suffixes are: -ise, -en, -ate, -(i)fy. By far the most common affix in academic English is -ise.


e.g. prefix + verb right arrow verb

Prefix Meaning Examples
re- again or back restructure, revisit, reappear, rebuild, refinance
dis- reverses the meaning of the verb disappear, disallow, disarm, disconnect, discontinue
over- too much overbook, oversleep, overwork
un- reverses the meaning of the verb unbend, uncouple, unfasten
mis- badly or wrongly mislead, misinform, misidentify
out- more or better than others outperform, outbid
be- make or cause befriend, belittle
co- together co-exist, co-operate, co-own
de- do the opposite of devalue, deselect
fore- earlier, before foreclose, foresee
inter- between interact, intermix, interface
pre- before pre-expose, prejudge, pretest
sub- under/below subcontract, subdivide
trans- across, over transform, transcribe, transplant
under- not enough underfund, undersell, undervalue, underdevelop



e.g. Suffix used to form verbs with the meaning “cause to be”.

Suffix Example
-ise stabilise, characterise, symbolise, visualise, specialise
-ate differentiate, liquidate, pollinate, duplicate, fabricate
-fy classify, exemplify, simplify, justify
-en awaken, fasten, shorten, moisten




The most common prefixes used to form new nouns in academic English are: co- and sub-. The most common suffixes are: -tion, -ity, -er, -ness, -ism, -ment, -ant, -ship, -age, -ery. By far the most common noun affix in academic English is -tion.

e.g. prefix + noun right arrow noun

Prefix Meaning Examples
anti- against anticlimax, antidote, antithesis
auto- self autobiography, automobile
bi- two bilingualism, biculturalism, bi-metalism
co- joint co-founder, co-owner, co-descendant
counter- against counter-argument, counter-example, counter-proposal
dis- the converse of discomfort, dislike
ex- former ex-chairman, ex-hunter
hyper- extreme hyperinflation, hypersurface
in- the converse of inattention, incoherence, incompatibility
in- inside inpatient,
inter- between interaction, inter-change, interference
kilo- thousand kilobyte
mal- bad malfunction, maltreatment, malnutrition
mega- million megabyte
mis- wrong misconduct, misdeed, mismanagement
mini- small mini-publication, mini-theory
mono- one monosyllable, monograph, monogamy
neo- new neo-colonialism, neo-impressionism
out- separate outbuilding,
poly- many polysyllable
pseudo- false pseudo-expert
re- again re-organisation, re-assessment, re-examination
semi- half semicircle, semi-darkness
sub- below subset, subdivision
super- more than, above superset, superimposition, superpowers
sur- over and above surtax
tele- distant telecommunications,
tri- three tripartism
ultra- beyond ultrasound
under- below, too little underpayment, under-development, undergraduate
vice- deputy vice-president



e.g. Suffix added to a verb (V), noun (N) or adjective (A) right arrow noun

Suffix Meaning Examples
action/instance of V-ing alteration, demonstration
expansion, inclusion, admission
-er person who V-s
something used for V-ing
advertiser, driver
computer, silencer
-ment action/instance of V-ing development, punishment, unemployment
person who V-s assistant, consultant
-age action/result of V breakage, wastage, package
-al action/result of V denial, proposal, refusal, dismissal
action/result of V preference, dependence, interference
attendance, acceptance, endurance
-ery/-ry action/instance of V-ing
place of V-ing
bribery, robbery, misery
refinery, bakery


Suffix Meaning Examples
-er person concerned with N astronomer, geographer
-ism doctrine of N Marxism, Maoism, Thatcherism
-ship state of being N friendship, citizenship, leadership
-age collection of N baggage, plumage
Suffix Meaning Examples
-ity state or quality of being A ability, similarity, responsibility, curiosity
-ness state or quality of being A darkness, preparedness, consciousness
-cy state or quality of being A urgency, efficiency, frequency




Many adjectives are formed from a base of a different class with a suffix (e.g. -less, -ous). Adjectives can also be formed from other adjectives, especially by the negative prefixes (un-, in- and non-).

The most common suffixes are -al, -ent, -ive, -ous, -ful, -less.

e.g. Suffix added to verbs or nouns right arrow adjective

Suffix Example
-al central, political, national, optional, professional
-ent different, dependent, excellent
-ive attractive, effective, imaginative, repetitive
-ous continuous, dangerous, famous
-ful beautiful, peaceful, careful
-less endless, homeless, careless, thoughtless
-able drinkable, countable, avoidable,


e.g. negative + adjective right arrow adjective

Prefix Examples
un- unfortunate, uncomfortable, unjust
im-/in-/ir-/il- immature, impatient, improbable, inconvenient, irreplaceable, illegal
non- non-fiction, non-political, non-neutral
dis- disloyal, dissimilar, dishonest




e.g. base with both prefix and suffix

Adjectives: uncomfortable, unavoidable, unimaginative, inactive, semi-circular

Nouns: disappointment, misinformation, reformulation

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