improbably vs improbable

improbably is not an adjective while improbable is an adjective.

Word	Noun	Adjective	Verb	Adverb
improbably	No	No	No	Yes
improbable	No	Yes	No	No

improbably (adjective)	improbable (adjective)
	not likely to be true or to occur or to have occurred
	having a probability too low to inspire belief
	too improbable to admit of belief

improbably (adverb)	improbable (adverb)
not easy to believe