Nick, Matthew or Herbert in Dickens (6)
I believe the answer is:
I believe this clue is a double definition.
'nick' is the first definition.
(both can informally mean to steal)
'matthew or herbert in dickens' is the second definition.
(members of the Pocket family in Great Expectations)
(Other definitions for pocket that I've seen before include "Snooker target; pouch" , "Appropriate" , "Take for oneself" , "Small isolated group" , "Take unlawfully" .)