Cocaine hit becomes vice (5)
I believe the answer is:
clamp
'vice' is the definition.
(I've seen this in other clues)
'cocaine hit' is the wordplay.
'cocaine' becomes 'C' (drugs abbreviation).
'hit' becomes 'lamp' (lamp can mean to hit someone).
'c'+'lamp'='CLAMP'
'becomes' acts as a link.
(Other definitions for clamp that I've seen before include "band getting things together" , "Immobilise (wheels)" , "Pile of bricks" , "Make fast" , "Firmly press" .)