noun
rule violation; infringement of the rules
General term for breaking or not following a rule, often used in sports, games, or formal settings.
彼はルール違反で退場になった。
He was sent off for a rule violation.
その行為は明らかなルール違反だ。
That action is a clear infringement of the rules.
Compound of ルール (rule, from English) and 違反 (violation).