Catch red-handed (3)
I believe the answer is:
nab
'catch red-handed' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for nab that I've seen before include "Seize quickly" , "Catch; grab suddenly" , "Catch (thief) (colloq.)" , "Cop" , "Collar (sl.)" .)