louse

Etymology

From Middle English lous, lows, lowse, from Old English lūs, from Proto-West Germanic *lūs, from Proto-Germanic *lūs, from Proto-Indo-European *lewH-. See also West Frisian lûs, Dutch luis, German Low German Luus, German Laus; also Welsh llau (“lice”), Tocharian B luwo, maybe Sanskrit यूका (yūkā).

noun

1. A small parasitic wingless insect of the order Psocodea.
2. (colloquial, dated, not usually used in plural form) A contemptible person; one who is deceitful or causes harm.
   He said: "Thanks, friend; but you're wasting your time. You better warn Crocker. If that louse makes a play for me, he'll get hit with Chicago lightning!" 1946, Joseph Thompson Shaw, The hard-boiled omnibus: early stories from Black Mask, page 388
   It's then that those louses go back to their spouses. Diamonds are a girl's best friend. 1949, Diamonds Are a Girl's Best Friend (song)
   […] as she raised her guitar for the last loud chord, an unseen louse let loose a rubber-tipped arrow that landed right on her dark-skinned forehead. 1965 December, Phil Ochs, “That Was The Year That Weren't”, in Cavalier

verb

1. To remove lice from; to delouse.