fat hen vs good-king-henry

fat hen and good-king-henry both are nouns.

Word	Noun	Adjective	Verb	Adverb
fat hen	Yes	No	No	No
good-king-henry	Yes	No	No	No

As nouns, fat hen and good-king-henry are synonyms defined as:

fat hen and good-king-henry: European plant naturalized in North America; often collected from the wild as a potherb

Other synonyms of fat hen include allgood, Chenopodium bonus-henricus, wild spinach.

fat hen (noun)	good-king-henry (noun)
European plant naturalized in North America; often collected from the wild as a potherb	European plant naturalized in North America; often collected from the wild as a potherb