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

The plaintiffs, who are unnamed in the lawsuit, include two school bus drivers and three commercial drivers. —CBS News, 26 Feb. 2026

One of the best defenses in civil litigation is that the plaintiff has pleaded laws that are preempted by other laws. —Michael McCann, Sportico.com, 26 Feb. 2026

In Los Angeles, a consolidated group of cases with more than 1,600 plaintiffs, including more than 350 families and over 250 school districts, are accusing Instagram, YouTube, TikTok and Snap of deliberately designing platforms to be addictive to young users. —Amanda Chen, NBC news, 26 Feb. 2026

Houston attorneys Tony Buzbee and Crystal Del Toro, of the Buzbee Law Firm, represent the plaintiffs. —Melissa Renteria, San Antonio Express-News, 26 Feb. 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