Meaning of "Big Sister/Unnie"

Eon-Ni(Unnie)

Big Sister/Unnie언니/Unnie#덕질/팬덤#관계/연애#SNS2010s Meme

A term of endearment used to address a woman who is older than the speaker in close-knit circles; it is frequently used among friends or within fan communities and other emotionally close groups

"That member is my favorite, so I love the atmosphere where fans call each other unnie and cheer each other on."