Drapes ruined by butter (6)
I believe the answer is:
spread
'butter' is the definition.
(thesaurus)
'drapes ruined' is the wordplay.
'ruined' indicates an anagram.
'drapes' with letters rearranged gives 'SPREAD'.
'by' acts as a link.
(Other definitions for spread that I've seen before include "expansion?" , "Disseminate through padres" , "Open, fan out, unfold" , "Soft paste; large meal" , "Distribute or disperse widely" .)