1. 脆弱的;易受伤害的
    Someone who is vulnerable is weak and without protection, with the result that they are easily hurt physically or emotionally.

vulnerable

    e.g. Old people are particularly vulnerable members of our society.
           老年人是社会中尤为明显的弱势群体。

2. 易感染（某种疾病）的；易患病的
    If a person, animal, or plant is vulnerable to a disease, they are more likely to get it than other people, animals, or plants.

vulnerable的解释

    e.g. People with high blood pressure are especially vulnerable to diabetes...
           有高血压的人尤其易患糖尿病。
    e.g. Plants that are growing vigorously are less likely to be vulnerable to disease.
           生命力强的植物不容易得病。

3. 易受伤害的;易受影响的
    Something that is vulnerable can be easily harmed or affected by something bad.

    e.g. Their tanks would be vulnerable to attack from the air...
           他们的坦克易受到空袭。
    e.g. ...a table showing which cars are most vulnerable to theft...
           易被盗车辆一览表