bullet-proof
demonstrable
demonstrated
inarguable
incontrovertible
unanswerable
unarguable
unassailable
undeniable
unshakable
water-tight
absolute
actual
admitting no question
certain
confirmable
demonstratable
factual
historical
impenetrable
impregnable
inappealable
indisputable
indomitable
indubitable
inexpugnable
insuperable
intuitable
invincible
inviolable
invulnerable
irrefragable
irrefutable
irresistible
overpowering
overwhelming
provable
real
resistless
self-evident
sure
testable
unbeatable
unconfutable
unconquerable
uncontestable
unimpeachable
unquestionable
unrefutable
unsubduable
cogent
conclusive
corroborative
handed-down-from-god
infallible
irrevocable
tangible
transcendent
unambiguous
undeviating
undisputed
unequivocal
unwarrantable
well-attested