restive bull; bucking bull
Used especially in the context of bull riding or rodeo; a bull that is difficult to control.
Riding a bucking bull at a rodeo is dangerous.
Standard kanji spelling for a restive or bucking bull.
Less common variant; 暴れ牛 is preferred.
Compound of 暴れ (abare, 'rampaging') + 牛 (ushi, 'bull/cow'). The exact historical derivation is uncertain, but the term is straightforwardly descriptive.