catch someone napping
catch (one) napping
1. Literally, to discover that one is sleeping when one is not supposed to be. A: "Why was Bill fired?" B: "I heard they caught him napping at his at his desk."
2. By extension, to exploit or capitalize on one's inattention. We were able to sneak into the building because we caught the security guard napping. I scored a goal after I caught their defenseman napping.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
catch someone napping(of an action or event) find someone off guard and unprepared to respond. informal
Farlex Partner Idioms Dictionary © Farlex 2017