unexploited vs fallow

unexploited is not a noun while fallow is a noun.

Word	Noun	Adjective	Verb	Adverb
unexploited	No	Yes	No	No
fallow	Yes	Yes	No	No

unexploited (noun)	fallow (noun)
	cultivated land that is not seeded for one or more growing seasons

unexploited (adjective)	fallow (adjective)
not developed, improved, exploited or used	undeveloped but potentially useful
	left unplowed and unseeded during a growing season