tart vs lemony

tart is a noun but lemony is not a noun.

Word	Noun	Adjective	Verb	Adverb
tart	Yes	Yes	No	No
lemony	No	Yes	No	No

As adjectives, tart and lemony are synonyms defined as:

Other synonyms of tart include lemonlike, sourish, tangy.

tart (noun)	lemony (noun)
a small open pie with a fruit filling
a pastry cup with a filling of fruit or custard and no top crust
a woman who engages in sexual intercourse for money

tart (adjective)	lemony (adjective)
tasting sour like a lemon	tasting sour like a lemon
harsh