Arrest for robbery (5)
I believe the answer is:
pinch
This clue is a double definition.
'arrest' is the first definition.
('pinch' can be a synonym of 'arrest')
'robbery' is the second definition.
(thesaurus)
'for' acts as a link.
(Other definitions for pinch that I've seen before include "amount of salt?" , "Tweak" , "Squeeze painfully" , "Grip sharply; steal" , "Steal (colloq.); one felt by the poor" .)