Not necessarily, for something to be unbelievable, it would have to be unthinkable and incomprehensible. Many things are unquestionable, but these things are much less imponderable than things of unbelievable origin.
amazijng
depending on what you meant by unbelievable... positive: amazing, incredible, awesome, astonishing, mind-boggling. negative: doubtful, implausible, sketchy, unreal, unlikely.
Sensational; amazing, unbelievable,
unlikely , incredible , dubious , unbelievable .
A synonym for the adjective interesting that begins with U is unusual.
incredible, mindboggling, implausible, far-fetched, unlikely, fanciful, unreal, relieve, astonishing
arguable, contestable, "open to discussion," "in dispute," questionable, debatable, disputable, "wanting to quarrel"
Possibly "the accused"... doubtable, dubious, fishy, questionable, shaky, suspected, suspicious, thick, uncertain, unclear, unsure.
Main Entry:improbable  [im-prob-uh-buhl] Show IPAPart of Speech:adjectiveDefinition:not likelySynonyms:doubtful, dubious, fanciful, far-fetched, flimsy*,hundred-to-one, iffy, implausible, inconceivable,not expected, outside chance, questionable,rare, slim, slim and none, unbelievable, uncertain,unconvincing, unheard of, unimaginable, unlikely,unsubstantial, weakAntonyms:believable, likely, ostensible, plausible, possible,probable, tenable* = informal/non-formal usage
The Unbelievable was created in 1996.
The weather is so cold, it is unbelievable. It is unbelievable how stupid some people are!
The duration of The Unbelievable is 2700.0 seconds.