- louse
- O.E. lus, "parasitic insect infecting human hair and skin," from P.Gmc. *lus (cf. O.N., M.Du., O.H.G. lus, Ger. Laur). Slang meaning "obnoxious person" is from 1630s. The plural lice (O.E. lys) shows effects of i-mutation. Lousy is late 14c. lousi "infested with lice;" figurative use as a generic term of abuse dates from late 14c.; sense of "swarming with" (money, etc.) is Amer.Eng. slang from 1843. The verb meaning "to clear of lice" is from mid-15c.; to louse up "ruin, botch" first attested 1934.