knavishly vs slyly

knavishly and slyly both are adverbs.

Word	Noun	Adjective	Verb	Adverb
knavishly	No	No	No	Yes
slyly	No	No	No	Yes

As adverbs, knavishly and slyly are synonyms defined as:

Other synonyms of knavishly include artfully, craftily, cunningly, foxily, trickily.

knavishly (adverb)	slyly (adverb)
in an subtle, cunning manner	in an subtle, cunning manner