unprovoked
/ˌʌnprəˈvəʊkt/adjective
1- (of an attack, or a display of aggression or emotion) not caused by anything done or said（攻击, 侵略, 情感）未受挑衅的, 无缘无故的：
acts of unprovoked aggression.
无缘无故的侵略行径。
1.1
- (of a person) not provoked to do something（人）没有被激惹的。