Synonyms for rat

noun

1. A rodent

   mouse, muskrat, vermin; see pest 1, rodent.

   Varieties of rats include: white, black, brown, house, laboratory, longtailed, water, swamp, desert, marsh, tree, giant, field, bamboo, cotton, kangaroo, jerboa, river, pack, big-eared, short-eared, red-nosed.

2. *A deserter or betrayer

   informer, turncoat, fink*; see deserter, traitor.