untune vs tune

untune is not a noun while tune is a noun.

Word	Noun	Adjective	Verb	Adverb
untune	No	No	Yes	No
tune	Yes	No	Yes	No

untune (noun)	tune (noun)
	the adjustment of a radio receiver or other circuit to a required frequency
	the property of producing accurately a note of a given pitch
	a succession of notes forming a distinctive sequence

untune (verb)	tune (verb)
cause to be out of tune	adjust the pitches of (musical instruments)
cause to lose one's composure	adjust for (better) functioning