Street fight cancelled (6)
I believe the answer is:
struck
'cancelled' is the definition.
(striking is a kind of canceling)
'street fight' is the wordplay.
'street' becomes 'st' (abbreviation).
'fight' becomes 'ruck' (I've seen this before).
'st'+'ruck'='STRUCK'
(Other definitions for struck that I've seen before include "dismantled" , "Hit or impressed" , "Given blows - affected instantaneously" , "Hit as by lightning" , "hit hard" .)