Regularly said to be chivalrous? (7)
I believe the answer is:
nightly
'regularly' is the definition.
(happening every night)
'said to be chivalrous?' is the wordplay.
'said to be' shows a homophone (sound like).
'chivalrous?' becomes 'knightly' (like a knight).
'knightly' is a homophone of 'NIGHTLY'.
(Other definitions for nightly that I've seen before include "Nocturnal" , "Every day between sunset and sunrise" , "when Casanova in action?" , "When owls fly" , "as stars appear" .)