requiem vs keen

requiem and keen both are nouns.

Word	Noun	Adjective	Verb	Adverb
requiem	Yes	No	No	No
keen	Yes	Yes	Yes	No

As nouns, keen is a hyponym of requiem; that is, keen is a word with a more specific, narrower meaning than requiem:

requiem: a song or hymn of mourning composed or performed as a memorial to a dead person
keen: a funeral lament sung with loud wailing

requiem (noun)	keen (noun)
a song or hymn of mourning composed or performed as a memorial to a dead person	a funeral lament sung with loud wailing

requiem (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

requiem (verb)	keen (verb)
	express grief verbally