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
• 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

During the trial, after Cardi took the stand to deliver her testimony, several of her impassioned exchanges with the plaintiff's lawyer, Ron Rosen Janfaza, went viral due to her unfiltered, expletive-laced responses and animated expressions, including eye rolls and shrugs. —Charna Flam, People.com, 3 Sep. 2025

In December 2023, a new suit was filed by plaintiffs Jane Doe, a Kentucky woman using a pseudonym to conceal her identity, Planned Parenthood and the ACLU, against the Office of the Commonwealth's Attorney. —Marina Johnson, Louisville Courier Journal, 2 Sep. 2025

What To Know The case before the appeals court was brought by two groups of plaintiffs. —Sonam Sheth, MSNBC Newsweek, 2 Sep. 2025

Two other plaintiffs, a 10-year-old boy and his 3-year-old sister, don't have family in Guatemala and don't want to return, according to the group. —Arkansas Online, 1 Sep. 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