French, from Latin per excellentiam "by the way of excellence." French par "by, through, by way of, by means of" is from Latin per (see per). For second element, see excellence.
1630s, "turn aside or wander from the (right) way," from Late Latin deviatus, past participle of deviare "to turn aside, turn out of the way," from Latin phrase de via, from de "off" (see de-) + via "way" (see via). Meaning "take a different course, diverge, differ" is from 1690s. Related: Deviated; deviating. The noun meaning "sexual pervert" is attested from 1912.
1590s, "out of the common or direct way," from Latin devius "out of the way, remote, off the main road," from de via; from de "off" (see de-) + via "way, road" (see via). Compare deviate. Originally in the Latin literal sense; the figurative sense of "deceitful" is first recorded 1630s. Related: Deviously; deviousness. Figurative senses of the Latin word were "retired, sequestered, wandering in the byways, foolish, inconsistent."