Chant (6)
'chant' is the definition.
(I know that chant can be written as intone)
This is all the clue.
(Other definitions for intone that I've seen before include "Recite as a chant" , "Recite without inflection" , "Speak in chanting voice" , "Recite in a chanting voice" , "Sing (prayer) on one note" .)
(Other definitions for incantation that I've seen before include "Charm" , "magic words" , "Formula" , "20 across" , "Magic spell" .)
'chant' is the definition.
(chant can mean to sing)
This is the entire clue.
(Other definitions for sing that I've seen before include "Turn informer" , "Croon" , "Chorus" , "pipe" , "Confess" .)