complainant

complainant — noun

1. In a court case, the person or group that claims to have been harmed and asks th

1.nounC1
Definition

In a court case, the person or group that claims to have been harmed and asks the court to order the other side to make things right.

Example

The complainant told the judge that her neighbour had built a wall on her land.

complainant + that-clause for stating the claim

In this case, the complainant claims the company did not pay for the goods it received.

Common collocations
  • the complainant alleges / claims / argues
  • lawyers for the complainant
  • the complainant's case / evidence / statement
  • the complainant against the defendant
Synonyms
  • plaintiff

    the standard term in civil court cases; more technical than complainant

  • claimant

    someone who makes a legal claim, often in insurance or compensation contexts

  • accuser

    less formal; focuses on the act of accusing rather than the legal process

  • petitioner

    someone who formally petitions a court, especially in family or probate cases

Antonyms
  • defendant

    the person or group being sued or accused in court

  • accused

    the person charged with a crime; used mainly in criminal cases

Grammar Patterns

the complainant + verb

Usage Note

Frequently contrasted with the defendant or the accused in court contexts. This term appears mainly in written legal documents and news reports about court cases, not in everyday conversation.

Common Mistakes

The complainant complained about the food at the restaurant.
The complainant filed a lawsuit against the restaurant for serving spoiled food.
In legal English, 'complainant' refers only to someone who starts a formal court case, not someone who makes an everyday complaint.

Word family

Synonym discussion

Sense: noun/1

Complainant is a broad legal term for anyone who brings a formal complaint to court, but four related words cover more specific situations. Plaintiff is the standard term in civil lawsuits — you file a complaint as a plaintiff, but once the case begins, the court calls you the plaintiff, not the complainant. Claimant appears more often in insurance disputes or compensation claims, where no direct accusation is involved. Accuser is less formal and focuses on the person who says someone did something wrong, without requiring a court filing. Petitioner is used in specialised courts — family court for divorce or custody, or probate court for wills. In everyday legal news, complainant often appears in criminal reporting (the person who reports the crime), while plaintiff dominates civil case headlines.

plaintiff ↗claimant ↗accuserpetitioner

Common collocations

Nouns

Phrases

  • on behalf of the complainant
  • lawyers for the complainant

Prepositions

Etymology

LatinFrenchEnglish

Complainant comes from Anglo-French 'compleignant', the present participle of 'compleindre' (to complain). This traces back to Latin 'complangere', meaning 'to beat one's breast' or 'to lament deeply' — from 'com-' (together) and 'plangere' (to strike). The word entered English legal use in the 1400s, shifting from expressing grief to formally stating a grievance in court.