1. 积极的行动;倡议
    An initiative is an important act or statement that is intended to solve a problem.

initiative的反义词

    e.g. Government initiatives to help young people have been inadequate...
           政府在积极帮助年轻人方面做得还不够。
    e.g. There's talk of a new peace initiative.
           传闻有可能提出新的和平倡议。

2. 主动权
    In a fight or contest, if you have the initiative, you are in a better position than your opponents to decide what to do next.

    e.g. We have the initiative; we intend to keep it...
           我们拥有主动权;我们不打算放弃它。
    e.g. He paused enough to consider the options but never so long as to lose the initiative.
           他停顿了一会儿权衡自己有哪些选项,但并没有久到丧失主动权。

3. 主动性;积极性;进取心
    If you have initiative, you have the ability to decide what to do next and to do it, without needing other people to tell you what to do.

    e.g. She was disappointed by his lack of initiative.
           她对他缺少进取心感到失望。
    e.g. ...workers who are able to sort out problems on their own initiative.
           能主动解决问题的工人

4. 采取主动;首先采取行动
    If you take the initiative in a situation, you are the first person to act, and are therefore able to control the situation.

    e.g. We must take the initiative in the struggle to end the war...
           为尽早结束战争,我们必须抢先行动。
    e.g. She knew she had to take the initiative and maintain an aggressive game throughout.
           她知道自己必须采取主动，并且始终保持咄咄逼人的态势。