insignificant adj.

word-forming element meaning "not, opposite of, without" (also im-, il-, ir- by assimilation of -n- with following consonant, a tendency which began in later Latin), from Latin in- "not," cognate with Greek an-, Old English un-, all from PIE root *ne- "not."

In Old French and Middle English often en-, but most of these forms have not survived in Modern English, and the few that do (enemy, for instance) no longer are felt as negative. The rule of thumb in English has been to use in- with obviously Latin elements, un- with native or nativized ones.

1570s, "having or conveying a meaning," from Latin significantem (nominative significans), present participle of significare "make known, indicate" (see signify). Earlier in the same sense was significative; also significate (adj.) "indicated, signified"(early 15c.).

From 1590s as "serving as a sign or indication." Often "having a special or secret meaning," hence "important, weighty" (1761). Related: Significantly. The scientific significant figure is from 1680s. Significant other is attested by 1961, in psychology, "the most influential other person in the patient's world."

1690s, from insignificant + -ance. Earlier was insignificancy (1650s).