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

In November, a jury sided with Ferguson, and Judge Cotton Walker awarded more than $43.8 million to the plaintiffs on Monday, according to court documents. —Alex Sundby june 19, CBS News, 19 June 2025

Both sides, meaning the plaintiffs being the athletes and the defendants meaning the conferences and the NCAA. —Edgar Thompson, The Orlando Sentinel, 19 June 2025

On Tuesday, the court expanded the injunction to apply to any passport holder, not only the plaintiffs, pausing the policy while the lawsuit plays out. —Rose Evans, Idaho Statesman, 19 June 2025

The plaintiff in that case, Willie White, who was 65 at the time of the 2023 lawsuit, had been arrested twice for panhandling in the span of a month. —Vivienne Serret, Miami Herald, 18 June 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