farmland vs tilled land

farmland and tilled land both are nouns.

Word	Noun	Adjective	Verb	Adverb
farmland	Yes	No	No	No
tilled land	Yes	No	No	No

As nouns, farmland and tilled land are synonyms defined as:

farmland and tilled land: arable land that is worked by plowing and sowing and raising crops

Other synonyms of farmland include cultivated land, ploughland, plowland, tillage, tilth.

farmland (noun)	tilled land (noun)
a rural area where farming is practiced	arable land that is worked by plowing and sowing and raising crops
arable land that is worked by plowing and sowing and raising crops