- (freely used with adjectives, participles, and their derivative adverbs and nouns: less frequently used with certain other nouns) not; contrary to; opposite of: uncertain, uncomplaining, unemotionally, untidiness, unbelief, unrest, untruth
WordReference Random House Learner's Dictionary of American English © 2026
un-1 ,prefix.
un-2 ,prefix.
UN or U.N., an abbreviation of:
- un- is used very freely to form adjectives and the adverbs and nouns formed from these adjectives. It means "not,'' and it brings negative or opposite force:unfair, unfairly, unfairness; unseen;unfitting;unformed;
unheard-of;
unrest;
unemployment.
un-2 ,prefix.
-
- un- is attached to verbs, and means "a reversal of some action or state, or a removal, a taking away, or a release'':unbend;uncork;unfasten.
- un- is also attached to some verbs to intensify the meaning:unloose (= let loose with force).
UN or U.N., an abbreviation of:
- Government, United Nations.
Collins Concise English Dictionary © HarperCollins Publishers::
un- prefix
un- prefix forming verbs and verbal derivatives
- denoting reversal of an action or state: uncover, untangle
- denoting removal from, release, or deprivation: unharness, unman, unthrone
- (intensifier): unloose
un (ən),USA pronunciation pron. [Dial.]
UN ,
un-1 ,
un-2 ,
- Slang Termsone:young uns; He's a bad un.
UN ,
- Government, See United Nations (def. 1).
un-1 ,
- a prefix meaning "not,'' freely used as an English formative, giving negative or opposite force in adjectives and their derivative adverbs and nouns (unfair;
unfairly;
unfairness;
unfelt;
unseen;
unfitting;
unformed;
unheard-of;
un-get-at-able), and less freely used in certain other nouns (unrest;
unemployment).
- Middle English un-, on-, Old English; cognate with Dutch on-, Gothic, German un-, Old Norse ū-, ō-; akin to Latin in-, Greek an-, a-. See a-6, an-1, in-3
- See in- 3.
un-2 ,
- a prefix freely used in English to form verbs expressing a reversal of some action or state, or removal, deprivation, release, etc. (unbend;
uncork;
unfasten;
etc.), or to intensify the force of a verb already having such a meaning (unloose).
- Middle English, Old English un-, on-; cognate with Gothic and-, Dutch ont-, German ent-; akin to Latin ante, Greek antí; compare ante-, anti-
- See un- 1.
'un-' also found in these entries (note: many are not synonyms or translations):
Annan
- Ashdown
- Baroja
- Bresson
- Bunche
- Buñuel
- Changchun
- Cyprus
- East Timor
- Gulf War
- hyson
- in-
- Incheon
- Iraq
- Israel
- Kosovo
- Kunming
- Kuwait
- MacBride
- Mallarmé
- Namibia
- Nauru
- North Macedonia
- Palau
- Palestine
- particle
- peacekeeping
- Pérez de Cuéllar
- poco
- pontoon
- prefix
- privative
- Resnais
- Robinson
- Samoa
- Serbia
- Tanganyika
- Trieste
- UN
- 'un
- un-American
- unbosom
- uncouth
- ungainly
- unhouseled
- United Nations
- unkempt
- unriddle
- unwitting
- Afternoon of a Faun, The