what is a rat
Full Definition of RAT. 1. a: any of numerous rodents (Rattus and related genera) differing from the related mice especially by considerably larger size b: any of various similar rodents. 2. : a contemptible person: as a: one who betrays or deserts friends or associates b: scab 3b c: informer 2. 3.ull Definition of RAT. intransitive verb. 1. : to betray, desert, or inform on one's associates âusually used with on. 2. : to catch or hunt rats. 3. : to work as a scab. transitive verb. 1.