sing vs madrigal

sing is not a noun while madrigal is a noun.

Word	Noun	Adjective	Verb	Adverb
sing	No	No	Yes	No
madrigal	Yes	No	Yes	No

As verbs, madrigal is a hyponym of sing; that is, madrigal is a word with a more specific, narrower meaning than sing:

Other hyponyms of sing include solmizate, troll, hymn, carol.

sing (noun)	madrigal (noun)
	an unaccompanied partsong for 2 or 3 voices; follows a strict poetic form

sing (verb)	madrigal (verb)
make a whining, ringing, or whistling sound	sing madrigals
divulge confidential information or secrets
to make melodious sounds
produce tones with the voice
deliver by singing