英汉词典

1. （尤指艰巨的）任务，工作，事业
    An undertaking is a task or job, especially a large or difficult one.

    e.g. Organizing the show has been a massive undertaking.
           组织那场演出是一项浩大的工程。

2. 承诺；保证
    If you give an undertaking to do something, you formally promise to do it.

    e.g. The MOD gave an undertaking to Saville that it had provided him with all relevant material.
           国防部向萨维尔保证已向他提供了所有相关的资料。