Bringer of bad luck in gangster circles (6)
I believe the answer is:
hoodoo
'bringer of bad luck' is the definition.
(I've seen this before)
'gangster circles' is the wordplay.
'gangster' becomes 'hood' (I've seen this before).
'circles' becomes 'oo' (resembles two O's).
'hood'+'oo'='HOODOO'
'in' is the link.
(Other definitions for hoodoo that I've seen before include "Thing or person thought to cause bad luck" , "Thing or person thought to bring bad luck" , "Spells" , "Jinx" , "Bringer of bad luck" .)