Rob shilling from complacent chump (3)
I believe the answer is:
mug
This clue could be a double definition.
'rob' is the first definition.
(slang)
'shilling from complacent chump' is the second definition.
'mug' can be an answer for 'chump' (synonyms). I'm not sure about the 'shilling from complacent' bit.
Can you help me to learn more?
(Other definitions for mug that I've seen before include "Sucker - drinking vessel" , "Charlie" , "concentrate on studying" , "Drinking vessel for one easily deceived" , "Vessel for a bit of a fool" .)