adj. 25B6; adjective
I find his story incredible : UNBELIEVABLE, beyond belief, hard to believe, unconvincing, far-fetched, implausible, improbable, highly unlikely, dubious, doubtful; inconceivable, unthinkable, unimaginable, impossible; feeble, weak, thin, lame; informal hard to swallow/take, cock-and-bull.
an incredible feat of engineering : MAGNIFICENT, wonderful, marvellous, spectacular, remarkable, phenomenal, prodigious, breathtaking, extraordinary, unbelievable, amazing, stunning, astounding, astonishing, awe-inspiring, staggering, formidable, impressive, supreme, great, awesome, superhuman; informal fantastic, terrific, tremendous, stupendous, mind-boggling, mind-blowing, out of this world; poetic/literary wondrous.