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
• suer

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

For troops involved in the court battles as plaintiffs, leaving voluntarily now would likely hurt their standing in the case. —Lolita C. Baldor, Los Angeles Times, 6 June 2025

The plaintiff, Marlean Ames, alleges her employer, the Ohio Department of Youth Services, denied her a promotion and later demoted her, in both cases selecting gay candidates instead who were less qualified. —Devin Dwyer, ABC News, 5 June 2025

The two class action suits are among the first to challenge insurance companies over ghost networks, said Steve Cohen, a lawyer at Pollock Cohen in New York who is representing the plaintiffs in both cases as well as Mazzola. —Vicky Nguyen, NBC news, 5 June 2025

These holdings correctly explain that climate plaintiffs are using state court proceedings as a Trojan horse for a radical, full scale rework of national – indeed international – climate policies. —Jason Isaac, Oc Register, 4 June 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