fer·ret 1 
(fĕrĭt)
(fĕrĭt)n.
1. A domesticated mustelid mammal (Mustela furo syn. Mustela putorius subsp. furo) with an elongated flexible body, often kept as a pet and sometimes trained to hunt rats or rabbits.
2. A black-footed ferret.
v. fer·ret·ed, fer·ret·ing, fer·rets
v.tr.
1.
a. To hunt (rabbits, for example) with ferrets.
b. To drive out, as from a hiding place; expel.
2. To uncover and bring to light by searching. Often used with out: "Their work merely points the way for others to ferret out the core components of all proteins" (Natalie Angier).
3. To hound or harry persistently; worry.
v.intr.
1. To engage in hunting with ferrets.
2. To search intensively.
[Middle English furet, ferret, from Old French furet, from Vulgar Latin *fūrittus, diminutive of Latin fūr, thief; see bher-1 in the Appendix of Indo-European roots.]
ferret·er n.
ferret·y adj.