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

Liliana Rauer, one of the plaintiffs, experienced overwhelming relief. — Jo Yurcaba, NBC news, 18 July 2026

The plaintiff alleged Mills failed to sign at least one of the qualification documents, which was notarized in the District of Columbia instead of Florida. — David Zimmermann, The Washington Examiner, 17 July 2026

Taco Bell has been sued at least three times in federal court this week, with plaintiffs alleging negligence, breach of warranty and violations of deceptive trade practices law for allegedly selling contaminated lettuce. — Antonio Pequeño Iv, Forbes.com, 17 July 2026

The former staffers’ attorneys tried to force her to testify in this week’s trial against Basabe, and plaintiffs have pointed to her noncooperation as evidence of the alleged House cover-up of Basabe’s actions and silencing of potential witnesses. — Claire Heddles, Miami Herald, 17 July 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