Emerald Isle vs keen

Emerald Isle and keen both are nouns.

Word	Noun	Adjective	Verb	Adverb
Emerald Isle	Yes	No	No	No
keen	Yes	Yes	Yes	No

Emerald Isle (noun)	keen (noun)
an island comprising the republic of Ireland and Northern Ireland	a funeral lament sung with loud wailing

Emerald Isle (adjective)	keen (adjective)
	excellent
	intense or sharp
	having or demonstrating ability to recognize or draw fine distinctions
	having a sharp cutting edge or point
	painful as if caused by a sharp instrument

Emerald Isle (verb)	keen (verb)
	express grief verbally