The Collaborative International Dictionary of English v.0.48:

Ferret \Fer"ret\, n. [F. feret, dim. or fer iron, L. ferrum.]
   (Glass Making)
   The iron used for trying the melted glass to see if is fit to
   work, and for shaping the rings at the mouths of bottles.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Ferret \Fer"ret\, n. [F. furet, cf. LL. furo; prob. fr. L. fur
   thief (cf. Furtive); cf. Arm. fur wise, sly.] (Zool.)
   An animal of the Weasel family (Mustela furo syn. Putorius
   furo), about fourteen inches in length, of a pale yellow or
   white color, with red eyes. It is a native of Africa, but has
   been domesticated in Europe. Ferrets are used to drive
   rabbits and rats out of their holes. They are sometimes kept
   as pets.
   [1913 Webster +PJC]

The Collaborative International Dictionary of English v.0.48:

Ferret \Fer"ret\, v. t. [imp. & p. p. Ferreted; p. pr. & vb.
   n. Ferreting.] [Cf. F. fureter. See Ferret, n.]
   To drive or hunt out of a lurking place, as a ferret does the
   cony; to search out by patient and sagacious efforts; --
   often used with out; as, to ferret out a secret.
   [1913 Webster]

         Master Fer! I'll fer him, and firk him, and ferret him.
                                                  --Shak.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Ferret \Fer"ret\, n. [Ital. foretto, dim. of fiore flower; or F.
   fleuret. Cf. Floret.]
   A kind of narrow tape, usually made of woolen; sometimes of
   cotton or silk; -- called also ferreting.
   [1913 Webster]

WordNet (r) 3.0 (2006):

ferret
    n 1: musteline mammal of prairie regions of United States;
         nearly extinct [syn: black-footed ferret, ferret,
         Mustela nigripes]
    2: domesticated albino variety of the European polecat bred for
       hunting rats and rabbits
    v 1: hound or harry relentlessly
    2: hunt with ferrets
    3: search and discover through persistent investigation; "She
       ferreted out the truth" [syn: ferret out, ferret]

Moby Thesaurus II by Grady Ward, 1.0:

34 Moby Thesaurus words for "ferret":
   Argus, Cape polecat, ape, bar, bear, cat, cavy, chimp, chimpanzee,
   coon, eagle, foumart, glutton, groundhog, guinea pig, hawk,
   hedgehog, lynx, monk, monkey, mousehound, opossum, polecat,
   porcupine, possum, prairie dog, quill pig, raccoon, skunk, weasel,
   whistle-pig, wolverine, woodchuck, zoril



Easton's 1897 Bible Dictionary:

Ferret
   Lev. 11:30 (R.V., "gecko"), one of the unclean creeping things.
   It was perhaps the Lacerta gecko which was intended by the
   Hebrew word (anakah, a cry, "mourning," the creature which
   groans) here used, i.e., the "fan-footed" lizard, the gecko
   which makes a mournful wail. The LXX. translate it by a word
   meaning "shrew-mouse," of which there are three species in
   Palestine. The Rabbinical writers regard it as the hedgehog. The
   translation of the Revised Version is to be preferred.