Composed a serenade with notes missing (6)
I believe the answer is:
serene
'composed' is the definition.
(I've seen this before)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for serene that I've seen before include "Calm and unruffled, like a princely title." , "Placid" , "Peaceful and contented" , "Totally unagitated" , "Peaceful and unruffled" .)