Adieu (n.) - Farewell

used adieu in a sentence

Adieu means

1. to say goodbye forever

2. to bid farewell

Its usage is (but not limited to) when you pay a last visit to someone who's likely gonna die (e. g. an inmate waiting to be executed in few days) and it's also used when you think you'll never see this person again in your life.

Examples of adieu in a sentence

1. We bid each other adieu after the event by giving one another a handshake

2. The bride bid adieu to her parents and family, and having already taken the betrothal, she now assumes the black, and for ever do without the world and its pleasures.

I silently bid adieu to Jensen, watching his figure get smaller as my train begins heading towards its destination.