Strike is success (3)
I believe the answer is:
hit
This clue is a double definition.
'strike' is the first definition.
(I know that strike can be written as hit)
'is success' is the second definition.
(a hit is a commercial success)
(Other definitions for hit that I've seen before include "Thump" , "skier, perhaps" , "suit" , "Best-selling record" , "Popular song; strike" .)