Not impeachable; not to be called in question; exempt from liability to accusation; free from stain, guilt, or fault; irreproachable; blameless; as, an unimpeachable reputation; unimpeachable testimony.
source: Webster 1913
adjective satellite
beyond doubt or reproach
An unimpeachable source.
source: WordNet 3.0
free of guilt; not subject to blame
Has lived a blameless life. Of irreproachable character. An unimpeachable reputation.
source: WordNet 3.0
completely acceptable; not open to exception or reproach
Two unexceptionable witnesses. A judge's ethics should be unexceptionable.
