unimpeachable -- (beyond doubt or reproach; "an unimpeachable source")
blameless, inculpable, irreproachable, unimpeachable -- (free of guilt; not subject to blame; "has lived a blameless life"; "of irreproachable character"; "an unimpeachable reputation")
unexceptionable, unimpeachable -- (completely acceptable; not open to exception or reproach; "two unexceptionable witnesses"; "a judge's ethics should be unexceptionable")
(Sound)
