Name adopted by conventional poet (5)
I believe the answer is:
donne
'poet' is the definition.
(16th- and 17th- century poet John Donne)
'name adopted by conventional' is the wordplay.
'name' becomes 'n' (common abbreviation e.g. on forms).
'adopted by' is an insertion indicator (I've seen this in other clues).
'conventional' becomes 'done' (as in 'the done thing').
'n' placed into 'done' is 'DONNE'.
(Other definitions for donne that I've seen before include "English preacher and metaphysical poet, d. 1631" , "basic assumption" , "John -, English poet" , "Writer of poetry" .)