/ Dictionary / Index U unbelievable: Meaning and Definition of Find definitions for: un•be•liev•a•ble Pronunciation: (un"bi-lē'vu-bul), [key] — adj. too dubious or improbable to be believed: an unbelievable excuse. so remarkable as to strain credulity; extraordinary: the unbelievable fury of the storm; an unbelievable athlete. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: unbelievable (Thesaurus) unbelief unbeliever Related Content Daily Word Quiz: spectral Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language