1. What does it mean?
오피셜 borrows English 'official.' In sports, entertainment, and fan discussions it commonly means information announced by the relevant organization or responsible party.
Also written or said as opisyeol
2. The nuance
A commenter writing 오피셜 does not make a claim official. Look for the original announcement and distinguish confirmation from speculation or a reposted screenshot.
3. Examples
“공연 날짜는 아직 오피셜이 안 나와서 기다리는 중이야.”
The concert date hasn't been officially announced yet, so I'm waiting.
“소문 말고 주최 측 오피셜 링크를 보내 줘.”
Send me the organizer's official announcement, not the rumor.
Sources
References support the meaning and usage. Example sentences are written for NoCapWiki.