Slaps the cuffs on (4)
I believe the answer is:
nabs
'slaps the cuffs on' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for nabs that I've seen before include "Catches with bans" , "Snatches" , "Catches in the act" , "Collars" , "Arrests" .)