Smash, striding, with a tee shot (12)
I believe the answer is:
disintegrate
'smash' is the definition.
(I've seen this before)
'striding with a tee shot' is the wordplay.
'with' is a charade indicator (letters next to each other).
'shot' indicates an anagram.
'striding'+'a'+'tee'='stridingatee'
'stridingatee' anagrammed gives 'DISINTEGRATE'.
(Other definitions for disintegrate that I've seen before include "Break into little pieces" , "collapse" , "Fall apart - it isn't agreed (anag)" , "Smash" , "Lose all cohesion" .)