keen vs perceptive

keen is a noun but perceptive is not a noun.

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

keen (noun)	perceptive (noun)
a funeral lament sung with loud wailing

keen (adjective)	perceptive (adjective)
excellent	having the ability to perceive or understand; keen in discernment
intense or sharp	of or relating to perception
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

keen (verb)	perceptive (verb)
express grief verbally