ETYM Latin incredibilis: cf. Old Fren. incredible. Related to In- not, and Credible.
Beyond belief or understanding; SYN. unbelievable.
Too improbable for belief ; also; of such a superlative degree as to be hard to believe
Not easy to believe; SYN. improbably, implausibly, unbelievably.
In an incredulous manner; SYN. unbelievingly, disbelievingly.