Smashing red vase is detrimental (7)
I believe the answer is:
adverse
'detrimental' is the definition.
(I've seen this in another clue)
'smashing red vase' is the wordplay.
'smashing' indicates anagramming the letters.
'red'+'vase'='redvase'
'redvase' anagrammed gives 'ADVERSE'.
'is' is the link.
(Other definitions for adverse that I've seen before include "Contrary -- inauspicious" , "Unfavourable to evaders" , "Detrimental" , "'Contrary, untoward (7)'" , "Inimical" .)