complainant

American  

[kuhm-pley-nuhnt] / kəmˈpleɪ nənt /

noun

1. a person, group, or company that makes a complaint, as in a legal action.

---

complainant British  

/ kəmˈpleɪnənt /

noun

1. law a person who makes a complaint, usually before justices; plaintiff

---

Etymology

Origin of complainant

1375–1425; late Middle English < Anglo-French compleignant (present participle of compleindre ). See complain, -ant

Explanation

In law, the person who accuses someone else of wrongdoing is sometimes called the complainant. You are the complainant if you sue your neighbor for building a chicken coop on your property. Although there are some technical differences in the way legal experts use the terms, a complainant is essentially the same as a plaintiff. They're both ways to refer to an accuser, or someone bringing an official grievance against someone else. Since the 15th century, complainant has been used to mean "one who makes a formal complaint in court, " from complain.

Example Sentences

In all of the documents Mr. Clark pored over, however, he didn’t find a single female complainant.

From The Wall Street Journal • Mar. 27, 2026

Anderson "desisted" when the woman did not say yes and left the bedroom, at which point the complainant heard her vomiting in the bathroom.

From BBC • Mar. 9, 2026

Harris said he had considered the possibility that Donaldson's reported comments could be a "form of control" against the complainant.

From BBC • Feb. 19, 2026

A spokesman for Lambeth Palace said Church authorities had written to the complainant - known as N - to outline the next steps.

From BBC • Dec. 11, 2025

“No,” he said, “we have attempted to interview the so-called complainant and he denies that he was ever assaulted.”

From "Long Walk to Freedom" by Nelson Mandela

Related Words

• accuser
• claimant
• plaintiff