Carefree song syllables (3-2)
I believe the answer is:
tra-la
'carefree song syllables' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for tra-la that I've seen before include "Joyous refrain in song" , "Ironic; expression of joy or gaiety" , "Sound made when humming a song" , "Expression of joy or gaiety, musically" , "The flowers that bloom in the spring -- -- (Mikado)" .)