unimpeachable
US /ˌʌn.ɪmˈpiː.tʃə.bəl/
UK /ˌʌn.ɪmˈpiː.tʃə.bəl/
1.
無懈可擊的
of such a high standard of honesty and moral goodness that it cannot be doubted or criticized:
:
•
A spokesman said the Bishop was a man of unimpeachable integrity and character.