mid-15c., of wine, "muddy, not clear," from Old French impur (13c.), from Latin impurus "not pure, unclean, filthy, foul," from assimilated form of in- "not, opposite of" (see in- (1)) + purus "pure" (see pure).
In English, the subsequent order of sense appearance seems to be "earthly, mundane, not spiritual" (c. 1500); "obscene, lewd, unchaste, immoral" (1530s); "mixed with offensive matter, tainted" (1590s); "mixed or combined with other things" (without reference to foulness), 1620s. As a noun from 1784. Related: Impurely.
mid-15c., impurite, "thing which makes or is impure;" c. 1500, "fact or quality of being impure," from Latin impuritas "uncleanness" (in a moral sense), from impurus "not pure" (see impure). Related: Impurities.
in metallurgy, "impure and unfinished product of the smelting of copper or other ores," 1839, from French matte, from the adjective meaning "dull, dim" (see mat (adj.)).
1540s, "one who renders unclean or impure, one who profanes," agent noun from pollute (v.). Ecological sense is by 1958.
active component of chili peppers, 1851, from capsicum, the genus name of the plants from which it is extracted, + chemical suffixes. Capsicine (1816) was an earlier name of an impure form of it.
late 14c., "ceremonially unclean, profane;" c. 1400, "rendered impure or unclean," past-participle adjective from pollute (v.). Meaning "drunk" is from 1912, American English slang; ecological sense is by 1888.
c. 1600, "mixed with a foreign substance, impure; no longer simple or natural," past-participle adjective from sophisticate (v.). Of persons, with a positive sense, "worldly-wise, discriminating, cultured," from 1895.
c. 1400, "make impure by admixture," from Medieval Latin sophisticatus, past participle of sophisticare (see sophistication). From c. 1600 as "corrupt, delude by sophistry;" from 1796 as "deprive of simplicity." Related: Sophisticated; sophisticating. As a noun meaning "sophisticated person" from 1921.