credibly vs probably

credibly and probably both are adverbs.

Word	Noun	Adjective	Verb	Adverb
credibly	No	No	No	Yes
probably	No	No	No	Yes

As adverbs, credibly and probably are synonyms defined as:

credibly and probably: easy to believe on the basis of available evidence

Other synonyms of credibly include believably, plausibly.

credibly (adverb)	probably (adverb)
easy to believe on the basis of available evidence	with considerable certainty; without much doubt
	easy to believe on the basis of available evidence