Synonyms of unbelievable

Adjective

1. incredible (vs. credible), unbelievable, astounding, dumbfounding, dumfounding, fabulous, improbable, marvelous, marvellous, tall(prenominal), undreamed, undreamed of, undreamt, undreamt of, unimagined, implausible, incredulous, unconvincing#1, flimsy, unthinkable

usage: beyond belief or understanding; "at incredible speed"; "the book's plot is simply incredible"

2. improbable, unbelievable, unconvincing, unlikely, implausible (vs. plausible)

usage: having a probability too low to inspire belief

Definition and meaning of unbelievable (Dictionary)