Celebrate destiny, say (4)
I believe the answer is:
fete
'celebrate' is the definition.
(synonyms)
'destiny say' is the wordplay.
'destiny' becomes 'fate' (synonyms).
'say' indicates a 'sounds like' (homophone) clue.
'fate' sounds like 'FETE'.
(Other definitions for fete that I've seen before include "Outdoor festival" , "Celebrate; village fair" , "Organised outdoor party or charitable event" , "Festival; gala" , "Village event" .)