rat Definition

rat
noun

1. Any of various small rodents, similar to mice but larger, which are found worldwide in huge numbers, and are notorious pests and transmitters of disease.
2. Any of various unrelated rodents that resemble this animal, eg kangaroo rat.
3. colloq
Someone who is disloyal towards their friends, political party, etc.
4. colloq
A strike-breaker; a blackleg.
5. colloq
A despicable person.

verb, intr ratted, ratting

1. To hunt or chase rats.
2. colloq
To betray their trust or desert them.
Form: rat on someone (usually)
3. colloq
To work as a blackleg.

Derivative: ratter
noun

A dog or other animal that catches and kills rats.

Idiom: smell a rat

colloq
To sense that something is not as it should be.

Etymology: Anglo-Saxon ræt.