1. Sajangnim - boss
2. Seonbae/Sunbae - for people with more experience
3. (Name)-ssi - Mr/Ms/Mrs (formal) | used in business environment
4. (Name)-nim - Mr/Ms/Mrs (more formal than -ssi)
5. Oppa - close male friend/brother (by female)
6. Eonni/Unni - older female friend/sister (by female)
7. Hyeong/Hyung - older male friend/sibling (by male)
8. Nuna/Noona - older female friend/sibling (by male)
9. Ajusshi - middle-aged man; mister
10. Agassi - young lady who isn't married yet
11. imo-nim - A woman in her fifties to sixties (used in restaurant, casual atmosphere)
The number of terms will grow as the story progresses!