Gangster loves to be a bringer of misfortune (6)
I believe the answer is:
hoodoo
'a bringer of misfortune' is the definition.
(I've seen this before)
'gangster loves' is the wordplay.
'gangster' becomes 'hood' (I've seen this before).
'loves' becomes 'oo' (love means 0 in tennis).
'hood'+'oo'='HOODOO'
'to be' is the link.
(Other definitions for hoodoo that I've seen before include "Thing or person thought to cause bad luck" , "Jinx" , "Thing or person thought to bring bad luck" , "bringer of misfortune" , "Bad luck some people bring" .)