I. rat 1 /ræt/ BrE AmE noun [countable]
[ Language: Old English ; Origin: ræt ]
1 . an animal that looks like a large mouse with a long tail
2 . spoken someone who has been disloyal to you or deceived you:
But you promised to help us, you rat!
3 . look like a drowned rat to look very wet and uncomfortable
4 . (like) rats leaving the sinking ship used to describe people who leave a company, organization etc when it is in trouble
⇨ ↑ rat race , ↑ rats , ⇨ smell a rat at ↑ smell 2 (7)
II. rat 2 BrE AmE verb ( past tense and past participle ratted , present participle ratting ) [intransitive] informal
1 . if someone rats on you, they tell someone in authority about something wrong that you have done SYN grass on
rat on
They’ll kill you if they find out you’ve ratted on them!
2 . British English to not do what you had promised to do SYN go back on , renege on
rat on
He accused the government of ratting on its promises to the disabled.
rat somebody ↔ out American English informal
if someone rats you out, they are disloyal to you, especially by telling someone in authority about something wrong that you have done:
You can’t rat out your teammates.