let somebody drop

Từ điển Oxford Advanced Learner 8th

let sb/sth ˈdrop idiom
1. to do or say nothing more about sb/sth
•I suggest we let the matter drop.
2. to mention sb/sth in a conversation, by accident or as if by accident
•He let it drop that the Prime Minister was a close friend of his.
Main entry: ↑drop_idiom