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
• accuser
• appellant

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

Miami attorney Joseph DeMaria, a federal litigator who once worked in the Justice Department’s organized crime task force in South Florida, said the environmental plaintiffs have a strong argument challenging the appeals court’s ruling that halted the Alligator Alcatraz case. —Jay Weaver, Miami Herald, 9 Sep. 2025

The court consolidated two separate cases in which plaintiffs – seven small businesses and a dozen states — have successfully challenged the legality of the tariffs at issue. —Dan Mangan, CNBC, 9 Sep. 2025

The plaintiffs argued the displacement was motivated by a desire to limit readers' access to books with viewpoints that are unpopular and controversial in the area. —Taylor Seely, AZCentral.com, 8 Sep. 2025

Given the number of works Apple may have infringed upon, the plaintiffs, Hendrix and Roberson, have requested the court to turn their complaint into a class action and block the company from further infringement of this kind. —PC Magazine, 8 Sep. 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