Catching out (8)
I believe the answer is:
striking
I believe this clue is a double definition.
'catching' is the first definition.
(to catch can mean to hit or strike someone)
'out' is the second definition.
(I've seen this before)
(Other definitions for striking that I've seen before include "Conspicuous" , "not working" , "Conspicuously impressive" , "stopping work" , "Delivering a blow" .)