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 seeks damages for privacy invasion, emotional distress, reputational harm and alleged placement on government watch lists. —Charlotte Observer, 8 Jan. 2026

The plaintiffs wanted Huddleston to invalidate the referendum and direct the council to arrange a new vote on a budget without the $4 million at question. —Don Stacom, Hartford Courant, 7 Jan. 2026

Howard, however, rejected a request by the plaintiffs’ attorneys to reinstate to the Medicaid program people who have lost benefits and not been reinstated. —Jim Saunders, Sun Sentinel, 7 Jan. 2026

The identity of the plaintiff remains anonymous. —Natasha Dye, PEOPLE, 7 Jan. 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