Oscar writes melody outside. (7)
I believe the answer is:
openair
'oscar' is the definition.
I know nothing about this answer so I cannot tell whether it can be defined by this definition.
'melody outside' is the wordplay.
I cannot really understand how this works, but
'melody' could be 'air' (synonyms) and 'air' is present in the answer.
'outside' could be 'open' (open is a kind of outside) and 'open' is present in the answer.
No letters remain.
This explanation may well be incorrect...
'writes' acts as a link.
Can you help me to learn more?
(Other definitions for openair that I've seen before include "Outdoor" , "taking place out of doors" .)