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
• 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

While plaintiff attorneys have embraced more dynamic presentations in trucking litigation, defense attorneys have been slower to adapt, according to Dunnells. —Lars Daniel, Forbes.com, 6 Aug. 2025

Josh Chatten-Brown, an attorney for the plaintiffs, said his clients’ lawsuit aims to address how the city processes ADU projects broadly, not just in Pacific Beach. —Jemma Stephenson, San Diego Union-Tribune, 5 Aug. 2025

At the time McCormick also rejected an equally unprecedented and massive fee request by plaintiff attorneys, who argued that they were entitled to legal fees in the form of Tesla stock valued at more than $5 billion. —Michelle Chapman, Fortune, 4 Aug. 2025

DeSantis vowed to keep the reforms in place amid efforts by some lawmakers to reinstate legal fees for plaintiffs who successfully challenge insurers’ initial claim settlement offers. —Ron Hurtibise, Sun Sentinel, 4 Aug. 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