선생

〔先生〕

1. teacher; instructor
A person whose job it is to teach.

2. professional
(polite form) A person who excels in a certain field of study or has excellent skills.

3. professional; master
(figurative) A person who has rich experience in or knows well about something.

4. Mr.; Mrs.; Doctor
(polite form) A word coming after one's last name or title, etc.