un-

un-

The prefix un- is used to form negatives of words with two types of meaning: (1) denoting the opposite of an adjective or its derivative (uneducated, unhappiness), and (2) denoting a reversal of the action implied by a verb (undress, unlock). Some adjectival forms in un- have a special and usually unfavourable sense (unprofessional, unscientific) and when a neutral classificatory form is needed non- is used instead (non-professional, non-scientific; see non-). For the choice between in- and un- forms, see in- and un-.