-nim (님) – A formal respectful way of addressing someone older than you.
-ssi (씨) – A formal way of addressing someone you do not know or are unfamiliar with.

Harabeoji (할아버지) – Grandfather, but also used to refer to elderly men.
Halmeoni (할머니) – Grandmother, but also used to refer to elderly women.

Abeoji (아버지) – Father.
Appa (아빠) – Father, but less formal, like “daddy” or “papa”.
Eomeoni (어머니) – Mother.
Umma (엄마) – Mother, but less formal, like “mummy” or “mama”.

Adeul (아들) – Son.
Ttal (딸) – Daughter.

Joka (조카) – Nephew.
Jokattal (조카딸) – Niece.

Ajussi (아저씨) – Middle aged man (Late 30's > Early 50's)
Ajumma (아줌마) – Middle aged woman (Late 30's > Early 50's)

Hyung (형) – Elder brother, but also used to refer to slightly older males by boys.
Noona (누나) – Elder sister, but also used to refer to slightly older females by boys.

Oppa (오빠) – Elder brother, but also used to refer to slightly older males by girls.
Unni (언니) – Elder sister, but also used to refer to slightly older females by girls.

Agassi (아가씨) – A younger woman of an unknown age.

Seonsaeng-nim (선생님) – Teacher, like Sensei.
Sunbae (선배) – Senior, like Sempai.
Hubae (후배) – Junior, like Kouhai.