catch someone with their pants down
catch (one) with (one's) pants down
To encounter or catch one by surprise in a vulnerable and often embarrassing position or situation. Thanks to that anonymous tip, we were able to catch the drug smugglers with their pants down—right when they were making the exchange. Jeff was caught with his pants down when he came to the meeting without having read the brief and the boss started firing questions at him.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
catch someone with their pants (or trousers) downcatch someone in an unprepared state or sexually compromising situation. informal
Farlex Partner Idioms Dictionary © Farlex 2017