a partially domesticated European polecat, esp an albino, used for hunting small rodents, e.g. rats, or kept as a pet: Mustela furo

informal an active and persistent search or searcher

informal (+ about/around) to search about or around

to hunt with ferrets

to hunt (rats, etc) with ferrets

(usu + out) to drive (game) out, esp from covert or burrows