(ˈ)in, ən+ adjective
Etymology: Middle English, from Latin incredibilis, from in- in- (I) + credibilis credible — more at credible
1.
a. : surpassing belief : too extraordinary and improbable to admit of belief
an incredible cost
b. : hard to believe real or true : unlikely , improbable
the children's appetite was incredible
2. obsolete : incredulous , unbelieving
• in·credibleness “+ noun
• in·credibly “+ adverb