Misfeasance，nonfeasance，malfeasance在法律英语均有“不当行为”的含义，但是三者之间还是有所区别的，使用的语境也有所不同，以下最具体介绍：

①misfeasance，指不当履行某人本应合法行使的行为（the improper performance of some act which one may lawfully do），如在履行合同时犯有过失，其有主动不当行为导致他人损害的含义（active misconduct working positive injury to others）；在法律英语中，尤指（用权不当构成的）【违法行为】。

②nonfeasance，指对某人本应履行的职责采取不作为的态度（the omission of an act which one ought to do），消极或未采取对他人的保护（passive inaction or a failure to take steps to protect others from harm）；在法律英语中，强调（责任、义务等的）【未履行】

③malfeasance 则为“渎职”，指行使了某人本完全不应当行使的行为（the doing of an act which one ought not to do at all），在法律英语中，强调(公共官员的)【渎职行为】。

参考双语例句：

Breach of duty/misfeasance — where a director or officer has misapplied or retained money or property of the company or where a misfeasance or breach of duty, fiduciary or otherwise, has caused the misapplication of assets or a loss to the company.

违反义务/行为不当——由于董事或高管挪用或占用公司资金或财产或由于行为不当、或违反受托义务或其他义务而造成资产挪用或公司损失。

Members noticed that the proposed scope of SDA was not limited to misfeasance committed only by directors and controlling shareholders of a company against the company, and sought clarification on whether the proposed scope was in line with that recommended by the Standing Committee on Company Law Reform (SCCLR). 委员察觉，法定衍生诉讼的拟议范围并不仅限于公司董事及控股股东针对公司所犯的不当行为，他们要求当局澄清，拟议范围是否与公司法改革常务委员会(常委会)所建议的范围一致。

Benin is also implementing an import-control programme aimed at ensuring the effective control of cargoes by scanning containers, which will also ensure transparency in the handling of maritime cargo and limit the opportunities for malfeasance during customs formalities.

贝宁还在执行一项重要的进口管制方案，以便通过扫描集装箱来确保有效控制货物，这也将确保海上货物处理过程的透明度，并且限制在通关手续中出现渎职行为的可能性。

Moreover, in the above case, the Supreme Court recognized that executive officers "might be removed by the President after notice and opportunity for public hearing for inefficiency, neglect of duty or malfeasance in office but for no other cause.

此外，最高法院又在上述案件中，确认行政人员可由总统罢免，但被罢免前会获得通知，并有机会接受公开聆讯，以确定他们是否缺乏效率疏忽职守或渎职。