greens vs leafy vegetable

greens and leafy vegetable both are nouns.

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

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

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

Other synonyms of greens include green.

greens (noun)	leafy vegetable (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