Saying goodbye and leaving is an example of adieu.
We bid our final adieus to our family, then boarded the ship, bound for America.
She thus bids adieu to all her friends, and having previously taken the white veil, the betrothal, she now assumes the black, and for ever forswears the world and its pleasures.
Adieu, dear and kind friend; may our divine Saviour and His most Holy Mother keep you in their holy and all-powerful care!
After a few more banalities Dickinson Faust rose, shook Dean's hand, patted his shoulder and bid a cheery adieu.