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

But for those who are named plaintiffs in state-level lawsuits over the same issue? — Matt Piper, New York Times, 22 Aug. 2026

In the Texas case, a jury awarded more than $50 million to plaintiffs Neil Heslin and Scarlett Lewis. — Reuters, USA Today, 22 Aug. 2026

As part of the pre-trial process, Martinez-Olguín also indicated that Paramount and the plaintiffs would engage in mediation. — Brian Stelter, CNN Money, 22 Aug. 2026

That case left Harry facing a potential bill for millions of pounds after the court ruled the plaintiffs were liable for the publisher’s legal fees. — ABC News, 21 Aug. 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