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 of plaintiff

• 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

One of the plaintiffs was Buaite Againn, the investment vehicle run by Davis’ former BeautyKind business partner. —Daniel Libit, Sportico.com, 12 May 2026

The plaintiffs in the California suit claim they were misled by deceptive labeling when purchasing the product more than a dozen times in California stores. —Itzel Luna, Los Angeles Times, 12 May 2026

Altman could only watch from the courtroom audience for the first two weeks of the trial as lawyers for Musk, the plaintiff, put on his case. —David Ingram, NBC news, 12 May 2026

The suit says the plaintiffs are seeking compensatory and punitive damages. —Sarah Perkel, USA Today, 12 May 2026

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