1. 武器;兵器
    A weapon is an object such as a gun, a knife, or a missile, which is used to kill or hurt people in a fight or a war.

    e.g. ...nuclear weapons.
           核武器

2. (用于应付困境的)工具，手段
    A weapon is something such as knowledge about a particular subject, which you can use to protect yourself or to get what you want in a difficult situation.

    e.g. I attack politicians with the one weapon they don't have, a sense of humor.
           我运用一种政客不具备的武器攻击他们，那就是幽默感。