affair

a difficult affair to manage

an affair of honor, a duel;  an affair of love, an intrigue

He used a hook-shaped affair with a long handle to unlock the car.

"Mean to say you been havin' an affair with Mrs. Peabody?"

Jerry's girlfriend said she wanted to go steady, but she was in an affair with one of his team-mates.

I was his affair and he was a little boy toy to me... Together it was our little scandal.

She also guessed that Lady Gladstone had not told them the affair had been planned some time ago. “We are looking forward to visiting you on Friday, Lady Gladstone,” said Harriet. “Geoffrey thought I might have forgotten because you sent us your invitation such ages ago, but I said, 'My dear brother, how could I possibly forget an invitation from Lady Gladstone?'“ “How very odd,” commented the comte lazily. “Lady Gladstone was just telling us it was an impromptu affair.”

[S]he, with the greatest effrontery imaginable, unbuttons his breeches, and removing his shirt, draws out his affair, so shrunk and diminished that I could not but remember the difference, now cresfallen, or just faintly lifting its head.