Assume it's a 'no' for replacement gifts (9)
I believe the answer is:
donations
'gifts' is the definition.
(I know this)
'assume it's a no for replacement' is the wordplay.
'assume' becomes 'don' (I've seen this before).
'for replacement' indicates an anagram (I've seen this in other clues).
'its'+'a'+'no'='itsano'
'itsano' anagrammed gives 'ations'.
'don'+'ations'='DONATIONS'
(Other definitions for donations that I've seen before include "Contributions" , "Gifts" .)