impatient 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.

c. 1200, pacience, "quality of being willing to bear adversities, calm endurance of misfortune, suffering, etc.," from Old French pacience "patience; sufferance, permission" (12c.) and directly from Latin patientia "the quality of suffering or enduring; submission," also "indulgence, leniency; humility; submissiveness; submission to lust;" literally "quality of suffering." It is an abstract noun formed from the adjective patientem (nominative patiens) "bearing, supporting; suffering, enduring, permitting; tolerant," but also "firm, unyielding, hard," used of persons as well as of navigable rivers, present participle of pati "to endure, undergo, experience," which is of uncertain origin.

Patience, n. A minor form of despair, disguised as a virtue. [Ambrose Bierce, "Devil's Dictionary," 1911]

Meaning "quiet or calmness in waiting for something to happen" is from late 14c. Meaning "constancy in labor or exertion" is attested from 1510s. Meaning "card game for one person" is from 1816.