Lively tune (4)
I believe the answer is:
lilt
'lively tune' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for lilt that I've seen before include "Musical quality of voice" , "Pleasant gentle accent" , "Jaunty musical rhythm" , "Swing - music" , "Till to get light and pleasant rhythm" .)