To catch someone out means to cause them to make a mistake that reveals that they are lying about something, do not know something, or cannot do something.
[mainly British]
Detectives followed him for months hoping to catch him out in some deception. [V n P prep]
He did not like to be caught out on details. [V n P prep]
The government has been caught out by the speed of events. [beV-ed P + by]
See full dictionary entry for catch
catch out in British English
verb
(tr, adverb) informal, mainly British
to trap (a person), esp in an error or doing something reprehensible
catch out in American English
Chiefly British
to take notice of a person's error, inconsistency, or unacceptable action
See full dictionary entry for catch
Examples of 'catch out' in a sentence
catch out
The impact, mild though it was, knocked what breath she'd managed to catch out of Patience.