A decoration so often out of place (7)
I believe the answer is:
festoon
'a decoration' is the definition.
(festoon is a kind of decoration)
'so often out of place' is the wordplay.
'out of place' indicates an anagram.
'so'+'often'='sooften'
'sooften' anagrammed gives 'FESTOON'.
(Other definitions for festoon that I've seen before include "Ornamental chain/garland" , "Hung garland" , "Decorate with hanging ornaments" , "swag" , "Decoration" .)