Weasel \Wea"sel\, n. [OE. wesele, AS. wesle; akin to D. wezel, G. wiesel, OHG. wisala, Icel. hreyiv[=i]sla, Dan. v["a]sel, Sw. vessla; of uncertain origin; cf. Gr. ?, ?, cat, weasel.]

(Zo["o]l.) Any one of various species of small carnivores belonging to the genus Putorius, as the ermine and ferret. They have a slender, elongated body, and are noted for the quickness of their movements and for their bloodthirsty habit in destroying poultry, rats, etc. The ermine and some other species are brown in summer, and turn white in winter; others are brown at all seasons.

Malacca weasel, the rasse.

Weasel coot, a female or young male of the smew; -- so called from the resemblance of the head to that of a weasel. Called also weasel duck.

Weasel lemur, a short-tailed lemur (Lepilemur mustelinus). It is reddish brown above, grayish brown below, with the throat white.

Source: Webster's Revised Unabridged Dictionary (1913)