leaf mustard vs gai choi

leaf mustard and gai choi both are nouns.

Word	Noun	Adjective	Verb	Adverb
leaf mustard	Yes	No	No	No
gai choi	Yes	No	No	No

As nouns, leaf mustard and gai choi are synonyms defined as:

Other synonyms of leaf mustard include Brassica juncea, chinese mustard, indian mustard.

leaf mustard (noun)	gai choi (noun)
leaves eaten as cooked greens	Asiatic mustard used as a potherb
Asiatic mustard used as a potherb