Revolutionary veteran sneakily hides trap (7)
I believe the answer is:
ensnare
'trap' is the definition.
(I know that trap can be written as ensnare)
'revolutionary veteran sneakily hides' is the wordplay.
'revolutionary' says the letters should be written backwards.
'hides' indicates the answer is hidden within the clue.
'eransne' is hidden within 'veteran sneakily'.
'eransne' written backwards gives 'ENSNARE'.
(Other definitions for ensnare that I've seen before include "Capture, trap" , "Ecstatic expression of feeling" , "Catch as if in a trap or net" , "Ambush" .)