Definición de un- en inglés:

un-

prefijo

1(Added to adjectives, participles, and their derivatives) denoting the absence of a quality or state; not: unabashed unacademic unrepeatable
1.1The reverse of (usually with an implication of approval or disapproval, or with another special connotation): unselfish unprepossessing unworldly

Origen

Old English, of Germanic origin; from an Indo-European root shared by Latin in- and Greek a-.

Uso

The prefixes un- and non- both mean ‘not’, but there is often a distinction in terms of emphasis. un- tends to be stronger and less neutral than non-: consider the differences between unacademic and non-academic, for example ( his language was refreshingly unacademic; a non-academic life suits him).

Definición de un- en: