intoned vs singsong

intoned is not a noun while singsong is a noun.

Word	Noun	Adjective	Verb	Adverb
intoned	No	Yes	No	No
singsong	Yes	Yes	Yes	No

As adjectives, intoned and singsong are synonyms defined as:

intoned and singsong: uttered in a monotonous cadence or rhythm as in chanting

Other synonyms of intoned include chantlike.

intoned (noun)	singsong (noun)
	informal group singing of popular songs
	a regular and monotonous rising and falling intonation

intoned (adjective)	singsong (adjective)
uttered in a monotonous cadence or rhythm as in chanting	uttered in a monotonous cadence or rhythm as in chanting

intoned (verb)	singsong (verb)
	speak, chant, or declaim in a singsong
	move as if accompanied by a singsong