6 [transitive] to find someone doing something that they do not expect you to see, especially something wrong or illegal
catch someone doing something: Several times she’d caught him staring at her.
catch someone red-handed (=find someone doing something wrong or illegal): Diana was caught red-handed taking money from her mother’s purse.
catch someone in the act (of doing something): Burglars who are caught in the act have little chance of escaping punishment.
catch someone at it: They’ve been trying to catch her at it, but she’s too clever.
Synonyms and related words