weasel

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of various carnivorous mammals of the genus Mustela, having a long slender body, a long tail, short legs, and brownish fur that in many species turns white in winter.
• noun A person regarded as sneaky or treacherous.
• intransitive verb To be evasive; equivocate.

from The Century Dictionary.

• noun A small carnivorous digitigrade mammal of the restricted genus Putorius, of the family Mustelidæ, related to the stoat or ermine, ferret, and polecat of the same genus, and less intimately to the marten or sable of the genus Mustela of the same family.
• noun The weasel-coot.
• noun A lean, mean, sneaking, greedy fellow.

from the GNU version of the Collaborative International Dictionary of English.

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

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The least weasel, Mustela nivalis.
• noun Any of the carnivorous mammals of the genus Mustela, having a slender body, a long tail and usually a light brown upper coat and light-coloured belly.
• noun The taxonomic family Mustelidae is also called the weasel family.
• noun A devious or sneaky person or animal.
• noun A type of yarn winder used for counting the yardage of handspun yarn. It most commonly has a wooden peg or dowel that pops up from the gearing mechanism after a certain number of yards have been wound onto the winder.
• verb transitive To achieve by clever or devious means.
• verb To gain something for oneself by clever or devious means.
• verb intransitive To engage in clever or devious behavior.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a person who is regarded as treacherous or sneaky
• noun small carnivorous mammal with short legs and elongated body and neck