(slang) A class ring bearing the image of a beaver, worn by graduates of MIT.

(slang) A motorcycle maintained at the lowest possible cost and usually painted black.

A motorist who drives through residential streets to avoid traffic congestion on the main roads.

(idiomatic) To sense something suspicious.

(idiomatic, colloquial, US) An old, unattractive automobile, purchased for little money, to be driven during brutal Great Lakes winters while the owner's "good" car remains garaged and protected from corrosive road salt for the season.

(Britain, colloquial, mildly vulgar) Extremely drunk.

A New World rat of the genus Oryzomys, having an exceptionally long tail.

(colloquial) A person who spends an unusually large amount of time at a gym.

(US) Any of various aquatic or semi-aquatic rodents from Florida and southern Georgia, especially Neofiber alleni; the muskrat. / (Australia) A water mouse, especially, the rakali, Hydromys chrysogaster.

(literally) A rat that lives on or along a river. / (chiefly derogatory) A lower-class person living on or along a river.