What does complainant mean?
A complainant is a person who makes a formal complaint or brings an accusation against someone else, typically within an official or legal framework such as a court, tribunal, police station, or regulatory body. The word signals that a grievance has moved beyond private grumbling into a structured process with records, procedures, and consequences. Complainants appear across many settings: a tenant alleging disrepair to a housing tribunal, a citizen reporting a crime to the police, or an employee raising misconduct through a company's channels. Although closely related to 'plaintiff' — the party who initiates a civil lawsuit — complainant is broader, covering anyone who lodges a complaint even when no lawsuit follows. The term carries a neutral-to-formal connotation and is firmly rooted in legal, bureaucratic, and journalistic language, where precision about who accused whom matters greatly.
nounA person who files a formal complaint or brings a legal claim against another party, especially in court proceedings or official grievance processes.
- A person who formally lodges a complaint, grievance, or accusation against another party, whether in a legal proceeding, tribunal, police report, or administrative process.
- In some jurisdictions (especially in criminal matters), a complainant is the person reporting an offence to authorities rather than a civil plaintiff suing for damages.
"The complainant alleged that her neighbour had repeatedly blocked the shared driveway."
"The complainant submitted evidence of the faulty wiring to the housing tribunal."
"Police recorded the details of the complainant before investigating the reported disturbance."
Standard regular plural; used when referring to multiple parties lodging complaints, as in class actions or grouped grievances.
"Several complainants came forward after the story broke in the press."
Every courtroom drama has one: the complainant is the voice that turns a private grievance into an official record — and the whole legal machinery begins with them.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of complainant
Complainant derives from the verb 'complain', which entered English from Old French 'compleindre', itself from Late Latin 'complangere' — 'to lament aloud' — formed from 'com-' ('together') and 'plangere' ('to beat the breast in grief'). The agent noun 'complainant' arose in Middle English via Anglo-Norman French legal usage, where it named the party lodging a charge. It shares this Latin root of public lamentation with cognates such as 'complaisant' (from the same French family) and 'placate'.
How complainant is actually used
Complainant carries a formal, legal-administrative register; it is standard in court documents, ombudsman reports, and workplace grievance procedures. In everyday speech people more often say 'the person complaining' or 'the caller'. In US civil litigation 'plaintiff' dominates, while 'complainant' is favoured in British usage, consumer-protection contexts, and cases involving complaints to regulators rather than lawsuits.
Easily confused with complainant
A plaintiff is specifically the party who initiates a civil lawsuit, while a complainant is a broader term for anyone filing a complaint, whether in court, to an ombudsman, or through an internal grievance process.
Complacent means smugly self-satisfied and unaware of danger, whereas complainant refers to a person making a complaint — the words merely sound similar.