Catch, as a criminal (3)
I believe the answer is:
nab
'catch as a criminal' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for nab that I've seen before include "Capture (slang)" , "Seize quickly" , "Pinch" , "Catch (thief) (colloq.)" , "Capture, catch" .)