Light melody (4)
I believe the answer is:
lilt
'light melody' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for lilt that I've seen before include "Gentle rhythm (in tune)" , "Jaunty rhythm in music" , "Buoyant motion" , "Light graceful swinging rhythm" , "Cheerful song" .)