Heroic Leander oddly dismissed as unmanly (7)
I believe the answer is:
epicene
'unmanly' is the definition.
(similar in meaning)
'heroic leander oddly dismissed' is the wordplay.
'heroic' becomes 'epic' (synonyms).
'oddly dismissed' indicates alternate letters (letters in odd-numbered positions removed).
The alternate letters of 'leander' are 'ene'.
'epic'+'ene'='EPICENE'
'as' is the link.
(Other definitions for epicene that I've seen before include "Hermaphroditic" , "Effeminate, effete" , "Common to both sexes" , "Unisex" , "camp" .)