1. (条件或环境)不利的，恶劣的
    Unfavourable conditions or circumstances cause problems for you and reduce your chances of success.

    e.g. Unfavourable economic conditions were blocking a recovery of the American insurance market...
           不利的经济形势阻碍着美国保险市场的复苏。
    e.g. We've got a fairly unfavourable exchange rate at the moment...
           眼下汇率对我们不利。

2. （反应）反对的，不赞同的
    If you have an unfavourable reaction to something, you do not like it.

    e.g. A more unfavourable response was given today by the Prime Minister...
           首相今天的回应更是表示反对。
    e.g. President Mubarak was particularly unfavourable to the idea...
           穆巴拉克总统尤其不赞同这一想法。

3. （比较）使相形见绌的
    If you make an unfavourable comparison between two things, you say that one thing seems worse than the other.

    e.g. He makes unfavourable comparisons between British and French cooking...
           他认为与法国菜相比，英国菜相形见绌。
    e.g. A younger child will benefit more from an older sister's help than from an unfavourable comparison between their progress.
           与一味地比较进步情况相比，年纪小一些的孩子会从姐姐的帮助中获益更多。