An inseparable verbal prefix or particle. It is prefixed: (a) To
verbs to express the contrary, and not the simple negative, of the
action of the verb to which it is prefixed; as in uncoil, undo, unfold.
(b) To nouns to form verbs expressing privation of the thing, quality,
or state expressed by the noun, or separation from it; as in unchild,
unsex. Sometimes particles and participial adjectives formed with this
prefix coincide in form with compounds of the negative prefix un- (see
2d Un-); as in undone (from undo), meaning unfastened, ruined; and
undone (from 2d un- and done) meaning not done, not finished. Un- is
sometimes used with an intensive force merely; as in unloose.
An inseparable prefix, or particle, signifying not; in-;
non-. In- is prefixed mostly to words of Latin origin, or else to words
formed by Latin suffixes; un- is of much wider application, and is
attached at will to almost any adjective, or participle used
adjectively, or adverb, from which it may be desired to form a
corresponding negative adjective or adverb, and is also, but less
freely, prefixed to nouns. Un- sometimes has merely an intensive force;
as in unmerciless, unremorseless.
Un- is prefixed to adjectives, or to words used adjectively.
To adjectives, to denote the absence of the quality
designated by the adjective
To past particles, or to adjectives formed after the analogy
of past particles, to indicate the absence of the condition or state
expressed by them
To present particles which come from intransitive verbs, or
are themselves employed as adjectives, to mark the absence of the
activity, disposition, or condition implied by the participle; as, -
---- and the like.
Those which have acquired an opposed or contrary, instead of
a merely negative, meaning; as, unfriendly, ungraceful, unpalatable,
unquiet, and the like; or else an intensive sense more than a prefixed
not would express; as, unending, unparalleled, undisciplined,
undoubted, unsafe, and the like.
Those which have the value of independent words, inasmuch as
the simple words are either not used at all, or are rarely, or at least
much less frequently, used; as, unavoidable, unconscionable,
undeniable, unspeakable, unprecedented, unruly, and the like; or
inasmuch as they are used in a different sense from the usual meaning
of the primitive, or especially in one of the significations of the
latter; as, unaccountable, unalloyed, unbelieving, unpretending,
unreserved, and the like; or inasmuch as they are so frequently and
familiarly used that they are hardly felt to be of negative origin; as,
uncertain, uneven, and the like.
Those which are anomalous, provincial, or, for some other
reason, not desirable to be used, and are so indicated; as, unpure for
impure, unsatisfaction for dissatisfaction, unexpressible for
inexpressible, and the like.
Un- is prefixed to nouns to express the absence of, or the
contrary of, that which the noun signifies; as, unbelief, unfaith,
unhealth, unrest, untruth, and the like.