Break to bits (7)
(Other definitions for smash that I've seen before include "Shatter violently" , "Completely destroy" , "something very popular" , "Violently break into pieces" , "Overarm volley" .)
'break to bits' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for shatter that I've seen before include "Break into many pieces" , "greatly upset" , "Break the minister into little pieces" , "wreck" , "Break into many bits" .)