形容词

1. 没有防备的；无人看管的
If something is unguarded, nobody is protecting it or looking after it.

2. 轻率的；不留神的
If you do or say something in an unguarded moment, you do or say it carelessly and without thinking, especially when it is something that you did not want anyone to see or know.

1. displaying or feeling no wariness

e.g. an unguarded remark

2. lacking protection or a guard

e.g. an unguarded gate
his unguarded queen was open to attack