1. What does it mean?
트롤 borrows 'troll' and often describes someone who spoils a cooperative game or provokes conflict online. 트롤링 names the disruptive behavior.
Also written or said as 트롤링, teurol
2. The nuance
People also throw the label at ordinary mistakes, but poor skill does not establish deliberate sabotage. Calling a teammate a 트롤 is an accusation, not constructive feedback.
3. Examples
“처음 하는 사람의 실수를 바로 트롤이라고 부르지 마.”
Don't immediately call a beginner a troll over a mistake.
“일부러 팀 진행을 방해하는 트롤은 신고했어.”
I reported the troll who was deliberately blocking the team's progress.
Sources
References support the meaning and usage. Example sentences are written for NoCapWiki.