■ noun
1》 a rodent resembling a large, long-tailed mouse, typically considered a serious pest. [ Rattus norvegicus ( brown ~ ), R. ~tus ( black or ship ~ ), and many other species.]
2》 informal a despicable person.
↘an informer.
3》 N. Amer. informal a person who is associated with or frequents a specified place: a mall ~.
■ exclamation ( ~s ) informal expressing mild annoyance.
■ verb ( ~s , ~ting , ~ted )
1》 hunt or kill ~s.
2》 informal desert one's party, side, or cause.
↘( ~ on ) break (an agreement or promise).
3》 ( ~ on or N. Amer. also ~ someone out ) informal inform on (someone).
Derivatives
~ting noun
Origin
OE ræt , prob. of Romance origin; reinforced in ME by OFr. ~ .