0 abbreviation for the United Nations: an international organization that was established in 1945 and aims to solve world problems in a peaceful way: --
1 used to add the meaning "not", "lacking", or "the opposite of" before adjectives, adverbs, verbs, and nouns: --
3 one: --
4 used to add the meaning "not," "lacking," or "the opposite of" to adjectives, adverbs, verbs, and nouns: --
unaided; unalterable; unaltered; unanticipated; unappreciated; unapproachable; unassigned; unassisted; unattainable; unbiased; uncommunicative; unconfined; unconvinced; uncultured; undefined; undiminished; uneconomical; unlicensed; unmodified; unmonitored; unmotivated; unobtainable; unpublished; unregulated; unrestricted; unrestrictive; unscheduled; unstressed; unstructured; unsustainable
5 abbreviation for United Nations (= an international organization that was established in 1945 to maintain world peace) --