unguarded

形容词 unguarded:

1. lacking protection or a guard
2. displaying or feeling no wariness

1. An unguarded remark; an unguarded glance.
   轻率的评论; 轻率的一瞥
2. The prisoner was left unguarded.
   那个犯人无人看守。
3. Never leave you luggage unguarded.
   千万注意看好自己的行李。