catch somebody with their trousers down

idiomPart oftrousers

catch somebody with their trousers down — idiom

1. To find someone unprepared for a situation, often causing them embarrassment.

1.idiom
Definition

To find someone unprepared for a situation, often causing them embarrassment.

Example

The sudden inspection caught the manager with his trousers down.

Did the pop quiz catch you with your trousers down?