unimpeachable vs unexceptionable

unimpeachable and unexceptionable both are adjectives.

Word	Noun	Adjective	Verb	Adverb
unimpeachable	No	Yes	No	No
unexceptionable	No	Yes	No	No

As adjectives, unimpeachable and unexceptionable are synonyms defined as:

unimpeachable and unexceptionable: completely acceptable; not open to exception or reproach

unimpeachable (adjective)	unexceptionable (adjective)
completely acceptable; not open to exception or reproach	completely acceptable; not open to exception or reproach
free of guilt; not subject to blame
beyond doubt or reproach