n. /lows/ ; v. /lows, lowz/ , n. , pl. lice /luys/ for 1-3, louses for 4, v. , loused, lousing .
n.
1. any small, wingless insect of the order Anoplura (sucking louse) , parasitic on humans and other mammals and having mouthparts adapted for sucking, as Pediculus humanus (body louse or head louse) and Phthirius pubis (crab louse or pubic louse) .
2. any insect of the order Mallophaga (bird louse, biting louse , or chewing louse) , parasitic on birds and mammals, having mouthparts adapted for biting.
3. See plant louse .
4. Slang. a contemptible person, esp. an unethical one.
v.t.
5. to delouse.
6. louse up , Slang. to spoil; botch: Miscasting loused up the movie.
[ bef. 900; 1910-15 for def. 4; ME lous ( e ), luse, pl. lise, lice; OE lus, pl. lys; c. D luis, G Laus, ON lus ]