drop a dime on
US /drɑp ə daɪm ɑn/
UK /drɑp ə daɪm ɑn/

1.
告發, 舉報
to inform the police or other authorities about someone's illegal activities
:
•
He threatened to drop a dime on his accomplice if he didn't get a larger share.
他威脅說,如果得不到更大的份額,就會告發他的同夥。
•
Someone must have dropped a dime on them, that's how the police found out.
一定是有人告發了他們,警察才發現的。