Composer has a part played back for a single man (8)
I believe the answer is:
bachelor
'a single man' is the definition.
'composer has a part played back' is the wordplay.
'composer' becomes 'bach' (Bach is an example).
'has' says to put letters next to each other.
'a part played' becomes 'role'.
'back' shows that the letters should be reversed in order.
'role' back-to-front is 'elor'.
'bach'+'elor'='BACHELOR'
'for' is the link.
(Other definitions for bachelor that I've seen before include "Unmarried person" , "Unmarried male" , "Graduate" , "he has no ties" , "leading man at start of Wedding Cantata" .)