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

In an email sent to priests of the archdiocese on Saturday afternoon and shared with NPR, Archbishop Ronald Hicks also said the deal had not yet been signed but that an agreement had been reached with plaintiffs and their attorneys. — Chandelis Duster, NPR, 24 Oct. 2026

The law would take effect seven days after the petition deadline passes or if a petition is denied, according to McKenna Raney, an attorney representing the plaintiffs. — Sophie Bates, Los Angeles Times, 24 Oct. 2026

Michael Bekesha, who represents the plaintiffs, says the Evanston program distributes funds based on race without specific harm identification. — ABC News, 24 Oct. 2026

If there are no appeals, the remaining funds after attorneys' fees and the lead plaintiffs are paid will be distributed among eligible class members. — Brian Sloan,dan Avery, CNBC, 23 Oct. 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