rat out 告发
rat on someone 向某人告密
A: Has he ratted on the group yet?
A：他向大家告密了吗？
B: Not yet, but he might do it soon.
B：还没有，但他可能很快就会这么做。
1) 告发，揭发
2) 充满了老鼠的
1. 告发，揭发
verb
1. Past tense and past participle of rat; to inform on someone, typically to the authorities.
Synonym: betrayed, snitched