Ben is possibly a writer (5)
I believe the answer is:
ibsen
'a writer' is the definition.
(dramatist Henrik Ibsen)
'ben is possibly' is the wordplay.
'possibly' is an anagram indicator.
'ben'+'is'='benis'
'benis' with letters rearranged gives 'IBSEN'.
(Other definitions for ibsen that I've seen before include "6 24 113 [SCAN-DIN-AVIAN] writer" , "Scandinavian playwright" , "Playmaker" , "Author of The Master Builder, d. 1906" , "Henrik -, dramatist from fourteen down (Hedda Gabler)" .)