Graduate with man, a nobleman (5)
I believe the answer is:
baron
'a nobleman' is the definition.
(baron is a kind of nobleman)
'graduate with man' is the wordplay.
'graduate' becomes 'BA' (someone with a Bachelor of Arts degree).
'with' is a charade indicator (letters next to each other).
'man' becomes 'ron' (short for Ronald).
'ba'+'ron'='BARON'
(Other definitions for baron that I've seen before include "Titled man for a portion of beef" , "A born nobleman" , "Lowest rank of British peerage" , "See nobleman" , "Noble rank" .)