Oriental flower for religious festival (6)
I believe the answer is:
easter
'religious festival' is the definition.
(I've seen this before)
'oriental flower' is the wordplay.
'oriental' becomes 'e'.
'flower' becomes 'aster' (aster is a kind of flower).
'e'+'aster'='EASTER'
'for' acts as a link.
(Other definitions for easter that I've seen before include "Annual religious festival" , "- Day; - bunny" , "Major Christian festival in April" , "Church festival" , "Christian feast of the Resurrection" .)