Excellency
Honorific title used for high-ranking officials such as ambassadors, ministers, and governors. Can be used as a standalone noun or as a suffix after a name or title.
His Excellency the Ambassador met with the President today.
Your Excellency, please come this way.
His Excellency the Ambassador will be attending.
From Chinese 閣下, literally 'below the tower/pavilion', originally a respectful way to address a high official without using their name directly.