mister
n. countable A1 Beginner US //ˈmɪstɝ// UK //mˈɪstɐ// mis·ter
n. a polite way to address a man when you do not know his name. You use it instead of his surname in casual or friendly situations.
n. a polite form of address for a man, used alone or before a surname. Common in informal and semi-formal contexts; less common in strict formal writing.
Good morning, mister. Can I help you?
The shop assistant greeted the customer with a polite 'Good afternoon, mister' before asking how she could help.
Though the title carries a certain deference, using 'mister' without a surname can sometimes imply a subtle social distance or playful familiarity depending on the tone.