slyly vs cunningly

slyly and cunningly both are adverbs.

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

As adverbs, slyly and cunningly are synonyms defined as:

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

slyly (adverb)	cunningly (adverb)
in an subtle, cunning manner	in an subtle, cunning manner
	in an attractive manner