unguarded

adj

• ① 不小心的,轻率的,掉以轻心的,大意的
  • I told him, in an unguarded moment, what I was going to do.我一不留神告诉了他我将做什么。

• ② 无防御的,无守备的;(平交道)无人看守的
  • She went out through an unguarded side door.她由没人看守的边门出去。
  • The building was unguarded on Sunday.那栋建筑物在星期日无人看守。