yellow-bellied vs chicken

yellow-bellied is not a noun while chicken is a noun.

Word	Noun	Adjective	Verb	Adverb
yellow-bellied	No	Yes	No	No
chicken	Yes	Yes	No	No

As adjectives, yellow-bellied and chicken are synonyms defined as:

Other synonyms of yellow-bellied include chickenhearted, lily-livered, white-livered, yellow.

yellow-bellied (noun)	chicken (noun)
	a domestic fowl bred for flesh or eggs; believed to have been developed from the red jungle fowl
	a foolhardy competition; a dangerous activity that is continued until one competitor becomes afraid and stops
	the flesh of a chicken used for food
	a person who lacks confidence, is irresolute and wishy-washy

yellow-bellied (adjective)	chicken (adjective)
easily frightened	easily frightened