unprovoked
adj. 无缘无故的；未受挑衅的
同义词
参考例子
1.The International Shark Attack File describes shark attacks as either provoked or unprovoked.
国际鲨鱼攻击档案形容鲨鱼攻击要么是受到了挑衅，要么是无故的。
2.Because of this unprovoked dastardly attack by Japan, I ask that the Congress declare a state of war.
因为日本发动了这一卑鄙的、衅式的袭击，我要求国会宣布全国进入战争状态。
3.Scorn, bitterness, unprovoked malignity, gratuitous desire of ill, ridicule of whatever was good and holy, all awoke to tempt , even while they frightened him.
轻蔑、狠毒、无缘无故的恶言秽行和歹意；对善良和神圣的事物妄加嘲弄，这一切全都会唤醒起来，虽说把他吓得要命，却仍在诱惑着他。
英文解释
adj.
1.occurring without motivation or provocation
网络释义
unprovoked
无谓的; 无缘无故的，非因触犯而发生的; 无缘无故的; 好么牙儿的=无缘无故的;
unprovoked assault
无正当理由的攻击;
unprovoked attack
无故发动的进攻; 无端攻击;
unprovoked aggression
无端侵略;
meaningless pointless senseless unprovoked
无谓的;