1. 无情的;残忍的;冷酷的
    If you say that someone is ruthless, you mean that you disapprove of them because they are very harsh or cruel, and will do anything that is necessary to achieve what they want.

    e.g. The President was ruthless in dealing with any hint of internal political dissent.
           在处理任何内部政治分歧的苗头时，总统都毫不留情。
    e.g. ...an invasion by a ruthless totalitarian power...
           残忍的极权主义国家的侵略

2. (行为等)坚决的，果断的，不留情面的
    A ruthless action or activity is done forcefully and thoroughly, without much concern for its effects on other people.

    e.g. Her lawyers have been ruthless in thrashing out a divorce settlement...
           她的律师在讨论离婚协议的过程中表现得非常坚决。
    e.g. Successfully merging two banks requires a fast and ruthless attack on costs.
           成功合并两家银行需要坚决快速地着手解决费用问题。