Operatic heroine, not quite typical (5)
I believe the answer is:
norma
'operatic heroine' is the definition.
(Norma is an opera by Vincenzo Bellini)
'not quite typical' is the wordplay.
'not quite' means to remove the last letter.
'typical' becomes 'normal' (similar in meaning).
'normal' with its last letter taken away is 'NORMA'.
(Other definitions for norma that I've seen before include "She incited Gauls v. Romans (Bellini)" , "Marilyn Monroe's real first name" , "Bellini opera - girl's name" , "musical work" , "Bellini heroine" .)