Article dropped by dirty pawnbroker (5)
I believe the answer is:
uncle
'pawnbroker' is the definition.
(old-fashioned term for a pawnbroker)
'article dropped by dirty' is the wordplay.
'article' becomes 'an' (English indefinite article).
'dropped by' is a deletion indicator.
'dirty' becomes 'unclean' (associated in meaning).
'unclean' with 'an' taken away is 'UNCLE'.
(Other definitions for uncle that I've seen before include "For example, Tom Cobbleigh" , "Pawnbroker's nickname" , "Grandfather's son" , "Brother of one's parent" , "A parent's brother" .)