Old boy only has perfume that’s discontinued (11)
I believe the answer is:
obsolescent
'discontinued' is the definition.
(thesaurus)
'old boy only has perfume' is the wordplay.
'old boy' becomes 'ob'.
'only' becomes 'sole' ('sole' can be a synonym of 'only').
'has' is a charade indicator (letters next to each other).
'perfume' becomes 'scent' ('scent' can be a synonym of 'perfume').
'ob'+'sole'+'scent'='OBSOLESCENT'
'that's' acts as a link.
(Other definitions for obsolescent that I've seen before include "Getting dated" , "no longer fresh?" , "past its sell-by date?" , "Outdated" , "Going out of use" .)