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 his clients’ lawsuit against the city, two plaintiffs say they were arrested for riding a scooter on the sidewalk. —Hannah Fry, Los Angeles Times, 6 Mar. 2026

The morning testimony challenged claims from the plaintiff, Tony Saxon, and another witness, handyman Jeromy Holding, that Ye’s plans for the property were constantly shifting. —Nancy Dillon, Rolling Stone, 5 Mar. 2026

In these cases, the plaintiffs’ names would be identified in court and related documents. —Gabriel Velasquez Neira, The Orlando Sentinel, 5 Mar. 2026

The plaintiffs signed that agreement without being allowed to have an attorney to review it, King wrote. —David K. Li, NBC news, 4 Mar. 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