impassive 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.

late 14c., passif, of matter, "capable of being acted upon;" of persons, "receptive;" also in the grammatical sense "expressive of being affected by some action" (opposed to active), from Old French passif "suffering, undergoing hardship" (14c.) and directly from Latin passivus "capable of feeling or suffering," from pass-, past-participle stem of pati "to suffer" (see passion).

The meaning "not active or acting" is recorded from late 15c.; the sense of "unresisting, not opposing, enduring suffering without resistance" is from 1620s. Related: Passively. As a noun, late 14c. as "a capacity in matter for being acted upon;" also in grammar, "a passive verb."

Passive resistance is attested in 1819 in Scott's "Ivanhoe" and was used throughout 19c.; it was re-coined by Gandhi c. 1906 in South Africa. Passive-aggressive with reference to behavior or personality characterized by indirect resistance but avoidance of direct confrontation is attested by 1971.

1789, from impassive + -ity. Earlier in the same sense was impassiveness (1640s).