Trap in a lie (5,3)
I believe the answer is:
catch out
(Other definitions for catch out that I've seen before include "Detect in a mistake or deceit" , "Detect in a mistake - gotcha" , "Trap" , "detect in error" .)
I believe the answer is:
catch out
(Other definitions for catch out that I've seen before include "Detect in a mistake or deceit" , "Detect in a mistake - gotcha" , "Trap" , "detect in error" .)