unbelievable (adjective) unbelievable: beyond the imagination
Sinonime: astonishing, beyond belief, cockamamie, cockeyed,
doubtful,
dubious, far-fetched, fishy,
flaky*,
flimsy*, for the birds, full of holes, harebrained,
implausible,
impossible,
improbable, incogitable,
inconceivable,
incredible, kooky, lamebrained, open to doubt,
outlandish, past belief,
phony,
preposterous,
questionable, reaching, scatterbrained, screwy,
staggering,
suspect,
thick*,
thin*,
too much*, unconvincing,
unimaginable, unsubstantial, unthinkable,
weak, won't hold water, won't wash
Antonime: believable,
credible,
plausible,
real