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

The plaintiff, identified as KGM in documents or Kaley, as her lawyers have called her during the trial, says her early use of social media addicted her to the technology and exacerbated depression and suicidal thoughts. —Arkansas Online, 13 Mar. 2026

The plaintiff, identified as KGM in documents or Kaley, as her lawyers have called her during the trial, says her early use of social media addicted her to the technology and exacerbated depression and suicidal thoughts. —ABC News, 12 Mar. 2026

In a statement, the plaintiffs argued that California’s rules were driving up the cost of cars. —Blanca Begert, Los Angeles Times, 12 Mar. 2026

The plaintiffs are represented by the nonprofit National Center for Law and Economic Justice, which advocates on behalf of low-income people, and a private law firm. —Jonathan Stempel, USA Today, 12 Mar. 2026

Word History

Etymology

Middle English plaintif, from Anglo-French, from pleintif, adjective

First Known Use

14th century, in the meaning defined above

Podcast

Get Word of the Day delivered to your inbox!

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