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

Talanoa Ili, a top-100 recruit in the Trojans’ vaunted 2026 class, joins Stanford quarterback Charlie Mirer as one of two lead plaintiffs in a class-action lawsuit that takes aim at the system implemented since the settlement ushered in a new era of direct payment from universities to athletes. —Ryan Kartje, Los Angeles Times, 10 June 2026

An injunction is a preliminary order in a litigation where the judge finds the plaintiff is likely to prevail on the merits and would suffer irreparable injury (meaning an injury money can’t fix) without an injunction. —Michael McCann, Sportico.com, 9 June 2026

The plaintiffs have until Wednesday evening to reply. —Ted Johnson, Deadline, 9 June 2026

According to councilman Bazaldua, Mendelsohn has withdrawn herself as a plaintiff in the lawsuit. —Nathalie Marie Palacios, CBS News, 9 June 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