leafy vegetable vs greens

leafy vegetable and greens both are nouns.

Word	Noun	Adjective	Verb	Adverb
leafy vegetable	Yes	No	No	No
greens	Yes	No	No	No

As nouns, leafy vegetable and greens are synonyms defined as:

leafy vegetable and greens: any of various leafy plants or their leaves and stems eaten as vegetables

Other synonyms of leafy vegetable include green.

leafy vegetable (noun)	greens (noun)
any of various leafy plants or their leaves and stems eaten as vegetables	any of various leafy plants or their leaves and stems eaten as vegetables