affair
/ə-ˈfer/
noun
commercial, professional, public, or personal business
matter, concern
a procedure, action, or occasion only vaguely specified; also : an object or collection of objects only vaguely specified
handles the company's public affairs
How I choose to live is my affair, not yours.
noun
a romantic attachment or episode between lovers
a lively enthusiasm
idiom
a situation or matter that someone should not interfere in by saying, doing, or asking anything about it
What I do in my spare time is none of your business.