Definition of "incredible"

The extinction of a species once so numerous seemed incredible.

1955, A. W. Schorger, The Passenger Pigeon: Its Natural History and Extinction, page vii

I get lost in what is credible and not credible. This whole thing gets so incredible when you consider wiping out whole nations, it is difficult to establish credibility.

1980 September 16, Senator John Glenn, quoted in William A. Schwartz et al., The Nuclear Seduction: Why the Arms Race Doesn’t Matter—And What Does, University of California Press (1990, 1993), page 29

The other may be that they sincerely believed it to be true, demonstrating an almost incredible lack of communication between themselves and their working engineers.

1986 June 6, Richard Feynman, “Personal observations on the reliability of the Shuttle”, in Presidential Commission on the Space Shuttle Challenger Accident, Report to the President

He therefore found revealed religion incredible in a literal sense, and, as Bayle had done before him, he radically separated morality from the practice of organized religion.

2009, Diarmaid MacCulloch, A History of Christianity, Penguin, published 2010, page 796