black eye vs shiner

black eye and shiner both are nouns.

Word	Noun	Adjective	Verb	Adverb
black eye	Yes	No	No	No
shiner	Yes	No	No	No

As nouns, black eye and shiner are synonyms defined as:

Other synonyms of black eye include mouse.

black eye (noun)	shiner (noun)
an unfortunate happening that hinders or impedes; something that is thwarting or frustrating	any of numerous small silvery North American cyprinid fishes especially of the genus Notropis
a swollen bruise caused by a blow to the eye	important food fish of the northern Atlantic and Mediterranean; its body is greenish-blue with dark bars and small if any scales
a bad reputation	something that shines (with emitted or reflected light)
	a swollen bruise caused by a blow to the eye