fallow vs unbroken

fallow is a noun but unbroken is not a noun.

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

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

fallow (adjective)	unbroken (adjective)
undeveloped but potentially useful	not broken; whole and intact; in one piece
left unplowed and unseeded during a growing season	marked by continuous or uninterrupted extension in space or time or sequence
	(especially of promises or contracts) not violated or disregarded
	(of farmland) not plowed
	not subdued or trained for service or use