plaintiff

noun

plain·​tiff ˈplān-təf 

: a person who brings a legal action compare defendant

Did you know?

We won't complain about the origins of plaintiff, although complain and plaintiff are distantly related; both can be traced back to plangere, a Latin word meaning "to strike, beat one's breast, or lament." Plaintiff comes most immediately from Middle English plaintif, itself an Anglo-French borrowing tracing back to plaint, meaning "lamentation." (The English word plaintive is also related.) Logically enough, plaintiff applies to the one who does the complaining in a legal case.

Synonyms

• complainant
• suer

Examples of plaintiff in a Sentence

the judge ruled that the plaintiff's lawsuit was groundless, and he dismissed it

Recent Examples on the Web

The plaintiffs said marketing campaigns from both PepsiCo and Coca-Cola over the years have misled consumers into believing the companies' products are environmentally sustainable. —Melina Khan, USA Today, 15 May 2025

The plaintiffs want the court to block Trump’s April 2 executive order imposing the tariffs. —Kevin Breuninger, CNBC, 13 May 2025

Trustees still face two lawsuits: one brought by Keller residents alleging violations of the Texas Open Meetings Act during discussions about the split and another with Keller parent Claudio Vallejo as the plaintiff alleging violations of the Voting Rights Act. —Matthew Adams, Fort Worth Star-Telegram, 13 May 2025

Our Lady of Guadalupe Parish, a Catholic parish in Logan Heights that has served immigrant peoples for its 100-year existence, where I am humbled to serve as its pastor, has entered as one of five plaintiffs in a suit against the federal government’s immigration agencies. —Scott Santarosa, San Diego Union-Tribune, 13 May 2025

Word History

Etymology

Middle English plaintif, from Anglo-French, from pleintif, adjective

First Known Use

14th century, in the meaning defined above

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Kids Definition

plaintiff

noun

plain·​tiff ˈplānt-əf 

: the complaining party in a lawsuit

Legal Definition

plaintiff

noun

plain·​tiff ˈplān-təf 

: the party who institutes a legal action or claim (as a counterclaim) see also complainant, complaint, libellant compare defendant, prosecution

Etymology

Middle French plaintif, from plaintif, adj., grieving, from plaint lamentation, from Latin planctus, from plangere to strike, beat one's breast, lament