Oppa is used in Korean culture by a female to a male, who is older than her by the
boundary of 10 years. Female's use this title for their
older brother, older male friend, or even in a
flirtatious way.
"Oppa~ You
promised me yesterday that we'd go to the beach, remember?" ^-^
"Oh, right.." >///<
"
JUNGKOOK OPPAAAAAAAAAAAAAAAAA!!!!!!"
"I'M NOT YOUR OPPAAAAAAAAAAAAAAAAA!!
111!"