1. (法律、制度或体系)严格的，刻板的，不可变更的
    Laws, rules, or systems that are rigid cannot be changed or varied, and are therefore considered to be rather severe.

    e.g. Several colleges in our study have rigid rules about student conduct...
           在我们的研究中，有几所大学制定了严格的学生行为规则。
    e.g. Hospital routines for nurses are very rigid.
           医院中护士的日常工作非常刻板。

2. 固执的;顽固的;刻板的
    If you disapprove of someone because you think they are not willing to change their way of thinking or behaving, you can describe them as rigid .

    e.g. She was a fairly rigid person who had strong religious views...
           她相当顽固，宗教观念极强。
    e.g. My father is very rigid in his thinking.
           我父亲的思想非常顽固。

3. 坚硬的;刚性的;不易弯曲的
    A rigid substance or object is stiff and does not bend, stretch, or twist easily.

    e.g. ...rigid plastic containers...
           坚硬的塑料容器
    e.g. These plates are fairly rigid.
           这些盘子非常坚硬。

4. (常因震惊或害怕)身体僵直的，不能动弹的，呆住的
    If someone goes rigid, their body becomes very straight and stiff, usually as a result of shock or fear.

rigid的反义词

    e.g. I went rigid with shock...
           我惊得僵在那里。
    e.g. Andrew went rigid when he saw a dog, any dog, anywhere.
           安德鲁过去只要看见狗，无论在哪里，无论什么狗，都会吓得一动不动。