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

Seven neighbors whose property was damaged by the explosion also are plaintiffs in the lawsuit. — Daniel Lempres, Sacbee.com, 25 July 2026

Live Nation lost its antitrust case against earlier this year, and the company and the dozens of plaintiff states await a judge’s ruling on potential remedies. — Ethan Millman, HollywoodReporter, 24 July 2026

In court filings, Tesla has claimed that Vaughn and other plaintiffs failed to establish that they were harassed or discriminated against on the basis of race. — Ethan Baron, Mercury News, 24 July 2026

Lawyers for Paramount reached the conclusion that the plaintiffs would likely prevail at the preliminary injunction stage, an executive involved in the matter told CNN. — Brian Stelter, CNN Money, 24 July 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