knavish vs sly

knavish and sly both are adjectives.

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

As adjectives, knavish and sly are synonyms defined as:

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

knavish (adjective)	sly (adjective)
marked by skill in deception	marked by skill in deception