If you describe an action, rule, or decision as arbitrary, you think that it is not based on any principle, plan, or system. It often seems unfair because of this.
双语例句
例： Arbitrary arrests and detention without trial were common.
不经审讯随意逮捕和扣押屡见不鲜。
例： a seemingly arbitrary deadline.
一个看来比较随意的截止期限。