knavish vs cunning

knavish is not a noun while cunning is a noun.

Word	Noun	Adjective	Verb	Adverb
knavish	No	Yes	No	No
cunning	Yes	Yes	No	No

As adjectives, knavish and cunning are synonyms defined as:

Other synonyms of knavish include crafty, dodgy, foxy, guileful, slick, sly, tricksy, tricky, wily.

knavish (noun)	cunning (noun)
	crafty artfulness (especially in deception)
	shrewdness as demonstrated by being skilled in deception

knavish (adjective)	cunning (adjective)
marked by skill in deception	showing inventiveness and skill
	marked by skill in deception
	attractive especially by means of smallness or prettiness or quaintness