I. ˈrat noun
Etymology: Middle English, from Old English ræt; akin to Old High German ratta rat and perhaps to Latin rodere to gnaw — more at rodent
Date: before 12th century
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. : a pad over which a woman's hair is arranged
4. : a person who spends much time in a specified place
a mall rat
• rat·like -ˌlīk adjective
II. verb
( rat·ted ; rat·ting )
Date: 1812
intransitive verb
1. : to betray, desert, or inform on one's associates — usually used with on
2. : to catch or hunt rats
3. : to work as a scab
transitive verb
1. : to give (hair) the effect of greater quantity (as by use of a rat)
2. : to inform on : turn in — usually used with out
ratted out his accomplice