Please tell, how to distinguish and use negative prefixes in, im, il, ir, un, dis, et. for different cases? Thanks in advance.

5 Answers


affirmative negative

political  apolitical

sexual asexual

theist atheist

Words that take dis- as a negative prefix may begin with a vowel or a consonant.

affirmative negative

agree disagree

comfort discomfort

mount dismount

orient disorient

Words that take il- as a negative prefix always begin with the letter l.

affirmative negative

legal illegal

legible illegible

literate illiterate

logical illogical

Words that take im- as a negative prefix always begin with the letter m or p.

affirmative negative

mobile immobile

moral immoral

perfect imperfect

possible impossible

Words that take in- as a negative prefix can begin with a vowel (except i or u) or a consonant.

affirmative negative

accurate inaccurate

eligible ineligible

organic inorganic

decentin decentsaneinsane

Note: There are many words that begin with in- that are not words with a negative prefix. For example:

word does not mean incline not cline 

indulge not dulge 

insist not sistin

voke not voke

Words that take ir- as a negative prefix always begin with the letter r.

affirmative negative

rational irrational

reconcilable irreconcilable

regular irregularre

sistible irresistible

Words that take non- as a negative prefix may begin with a vowel or a consonant.

affirmative negative

conformist nonconformist

essential nonessential

fiction nonfiction

sense nonsense

Words that take un- as a negative prefix may begin with a vowel or consonant.

affirmative negative

able unable

interesting uninteresting

usual unusual

comfortable uncomfortable

helpful unhelpful

prepared unprepared

Remember, not all words that appear to have a negative prefix are negative.

word does not mean

alike not like

discuss not cuss

universe not iverse

illuminate not luminate

important not portant 

involve not volve

irrigate not rigate



Thanks, there are some typos: resistible irresistible

sane insane



I gained access to this list at THIRUMAVALAVAN's blog.  Very good rules on negative prefixes from Agnes Sonik below..


whats for preparation???is it unpreparation or impreparation???


You want to add the prefix to an adjective. The '-tion' in your word indicates it is a noun. The adjective form is prepared. The correct negative prefix meaning "not prepared" is unprepared.

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