Flower not yet replaced (7)
I believe the answer is:
current
'flower' is the definition.
(I've seen this before)
'not yet replaced' is the wordplay.
I cannot really see how this works, but
'not' could be 'nt' (synonyms) and 'nt' is found within the answer.
This explanation may well be incorrect...
(Other definitions for current that I've seen before include "Flow, of a river say" , "flower" , "Electrical flow" , "Present - tide" , "In general use; flow" .)