Simple song (5)
(Other definitions for chant that I've seen before include "Repeated rhythmic song" , "Type of group singing" , "Recite singingly" , "Repetitive song" , "Intone - recite" .)
'simple song' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for ditty that I've seen before include "Short simple song" , "Air" , "Simple tune" , "Little tune" , "Light-hearted song" .)