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

Messages left Monday with plaintiffs' attorneys and Tesla were not immediately returned. —CBS News, 25 Nov. 2025

Messages left Monday with plaintiffs’ attorneys and Tesla were not immediately returned. —Mark Thiessen, Fortune, 25 Nov. 2025

According to plaintiffs, the law mandates that the governor had to distribute the federal benefits when available, no matter any other possible labor considerations. —Suzanne Blake, MSNBC Newsweek, 25 Nov. 2025

Cases that could have been settled quickly for a fraction of the ultimate cost have instead become years-long courtroom battles, driving millions of dollars in attorneys’ fees and million-dollar settlements with the plaintiffs, May and other attorneys said. —Chase Hunter, Mercury News, 24 Nov. 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