Often heroic, opener dismissed (7)
I believe the answer is:
nightly
'often' is the definition.
Both the definition and answer are adverbs. Perhaps you can see a link between them that I don't see?
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for nightly that I've seen before include "Regularly during the hours of darkness" , "when Casanova in action?" , "At the end of each day" , "Nocturnal" , "as stars appear" .)