One musical man returning is unoriginal (9)
I believe the answer is:
imitative
'unoriginal' is the definition.
(similar in meaning)
'one musical man returning' is the wordplay.
'one' becomes 'i' (Roman numeral).
'musical' becomes 'evita' (Andrew Lloyd Webber musical).
'man' becomes 'tim' (short for Timothy).
'returning' shows that the letters should be reversed in order.
'evita'+'tim'='evitatim'
'evitatim' back-to-front is 'mitative'.
'i'+'mitative'='IMITATIVE'
'is' is the link.
(Other definitions for imitative that I've seen before include "is like an ape" , "Copying" , "Mimicking or onomatopoeic" , "Following a model" , "Echoing" .)