unimpeachable
1. [ adjective ] beyond doubt or reproach
Examples:

"an unimpeachable source"

Related terms: unquestionable
2. [ adjective ] free of guilt; not subject to blame
Synonyms: inculpable irreproachable blameless
Examples:

"has lived a blameless life" "of irreproachable character" "an unimpeachable reputation"

Related terms: innocent
3. [ adjective ] (law) completely acceptable; not open to exception or reproach
Synonyms: unexceptionable
Examples:

"two unexceptionable witnesses" "a judge's ethics should be unexceptionable"

Related terms: acceptable
Similar spelling:   unimpeachably