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

According to court documents, GEO and the plaintiffs reached a settlement on Monday. — Christa Swanson, CBS News, 8 Nov. 2026

OpenAI faces several lawsuits from state AGs and plaintiff attorneys, taking cues from the social media suits in alleging that the design of ChatGPT can pose risks to children. — Jonathan Vanian, CNBC, 7 Nov. 2026

In approving the temporary stop, Chutkan said Virginia and the District of Columbia had shown the immediacy of the construction would cause real harm to the plaintiffs. — Matthew Daly, Arkansas Online, 7 Nov. 2026

After plaintiffs accused Wexner of attempting to evade subpoenas, a federal magistrate judge ultimately ordered him to testify. — Daniel Libit, Sportico.com, 7 Nov. 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