Open English Wordnet
Adjectives
(s)blameless, inculpable, irreproachable, unimpeachablefree of guilt; not subject to blame“has lived a blameless life”, “of irreproachable character”, “an unimpeachable reputation”
(s)unexceptionable, unimpeachablecompletely acceptable; not open to exception or reproach“two unexceptionable witnesses”, “a judge's ethics should be unexceptionable”