1. 紧靠；倚；碰
    If one thing is leaning or pressing against another, it is touching it.

    e.g. She leaned against him...
           她紧靠着他。
    e.g. On a table pushed against a wall there were bottles of beer and wine.
           在一张靠墙的餐桌上有啤酒和葡萄酒。

2. 反对（计划、政策、制度等）
    If you are against something such as a plan, policy, or system, you think it is wrong, bad, or stupid.

    e.g. Taxes are unpopular — it is understandable that voters are against them...
           税收不受欢迎——选民们反对是可以理解的。
    e.g. Joan was very much against commencing drug treatment.
           琼极力反对进行药物治疗。

3. 与…竞争；与…对阵
    If you compete against someone in a game, you try to beat them.

    e.g. The tour will include games against the Australian Barbarians...
           这次巡回赛将包括和澳大利亚野人队的比赛。
    e.g. Billy Hardy has pulled out of his second fight against Noel Carroll after a training accident.
           一次训练事故之后，比利·哈迪退出了和诺埃尔·卡罗尔的第二次比赛。

4. 反对；对抗
    If you take action against someone or something, you try to harm them.

    e.g. Security forces are still using violence against opponents of the government.
           安全部队仍然在使用武力镇压反对政府的人。
    e.g. ...an upsurge in racism against immigrants...
           对移民的种族歧视的高涨

5. 制止；预防；阻止
    If you take action against a possible future event, you try to prevent it.

    e.g. ...the fight against crime...
           打击犯罪
    e.g. They are arguing against hospital closures...
           他们据理反对关闭医院。

6. 违背，违抗（愿望、劝告或命令）
    If you do something against someone's wishes, advice, or orders, you do not do what they want you to do or tell you to do.

    e.g. He didn't want to go against the wishes of the German government...
           他不想违抗德国政府的意愿。
    e.g. He discharged himself from hospital against the advice of doctors.
           他不顾医生的劝告自行出院了。

7. 防备
    If you do something in order to protect yourself against something unpleasant or harmful, you do something which will make its effects on you less serious if it happens.

against的解释

    e.g. A business needs insurance against risks such as fire and flood...
           公司需要上保险以防备火灾、洪灾等风险。
    e.g. It has been claimed that wine helps protect against heart disease.
           有人声称葡萄酒有助于预防心脏病。

8. 不喜欢；对…存有芥蒂
    If you have something against someone or something, you dislike them.

    e.g. Have you got something against women, Les?...
           你对女性存有芥蒂吗，莱斯？
    e.g. I have nothing against foreigners.
           我对外国人并无芥蒂。

9. 违反（法律或规则）
    If something is against the law or against the rules, there is a law or a rule which says that you must not do it.

    e.g. It is against the law to detain you against your will for any length of time...
           无论强制扣押多长时间都属违法。
    e.g. We thought cheating was against the rules.
           我们认为作弊是违反规定的。

10. 迎着；逆着
    If you are moving against a current, tide, or wind, you are moving in the opposite direction to it.

    e.g. ...swimming upstream against the current...
           逆流往上游泳
    e.g. They were going to sail around the little island, against the tide.
           他们打算绕着小岛逆潮航行。

11. 以…为背景
      If something happens or is considered against a particular background of events, it is considered in relation to those events, because those events are relevant to it.

      e.g. The Pope has sent a message appealing for unity in his homeland, against a background of divisions in the Solidarity movement...
             团结运动中各派搞分裂，在此情况下教皇发出号召，呼吁祖国保持团结。
      e.g. The profits rise was achieved against a backdrop of falling metal prices.
             在金属价格下跌的背景下，利润提高了。

12. 和…对比；对照
      If something is measured or valued against something else, it is measured or valued by comparing it with the other thing.

      e.g. Our policy has to be judged against a clear test: will it improve the standard of education?...
             对我们的政策作出评判必须根据一条明确的准则：它是否会提高教育的水准？
      e.g. Check the operator's productivity against agreed targets...
             根据既定目标检验操作员的效率。

13. 与…相对；与…比较
      If you discuss a particular set of facts or figures as against another set, you are comparing or contrasting the two sets of facts or figures.

against的翻译

      e.g. Over 50% of divorced men regretted their divorce, as against 25% of women.
             离婚男性中有50%以上后悔离婚，与此相对，女性只有25%。

14. 不利于
      The odds against something happening are the chances or odds that it will not happen.

      e.g. The odds against him surviving are incredible.
             他活下来的概率非常小。

15. up against -> see up
      against the clock -> see clock