Incredible \In*cred"i*ble\, a. [L. incredibilis: cf. OF. incredible. See In- not, and Credible.]

Not credible; surpassing belief; too extraordinary and improbable to admit of belief; unlikely; marvelous; fabulous.

Why should it be thought a thing incredible with you, that God should raise the dead? --Acts xxvi. 8.

Source: Webster's Revised Unabridged Dictionary (1913)