complainant

noun

com·​plain·​ant kəm-ˈplā-nənt 

1

: the party who makes the complaint in a legal action or proceeding

2

: one who complains

Synonyms of complainant

• plaintiff

Examples of complainant in a Sentence

the complainant charged that the defendant had broken the ironclad contract that both had signed

Recent Examples on the Web

One anonymous complainant told the department that an elderly man had nearly drowned in the pool and was taken to a hospital. — Verónica Egui Brito, Miami Herald, 10 Aug. 2026

The complainant alleged that the driver of a minivan had pointed a firearm at them a few towns over. — Justin Muszynski, Hartford Courant, 7 Aug. 2026

The complainant, who was not identified in the initial case report, said Celeste was attacked by a dog and dragged through the woods. — Rafael Escalera Montoto, Arkansas Online, 5 Aug. 2026

None of the six complainants can be identified for legal reasons. — ABC News, 3 Aug. 2026

Word History

First Known Use

15th century, in the meaning defined at sense 1

Kids Definition

complainant

noun

com·​plain·​ant kəm-ˈplā-nənt 

1

: one who makes a legal complaint

2

: one who complains

Legal Definition

complainant

noun

com·​plain·​ant kəm-ˈplā-nənt 

: the party (as a plaintiff or petitioner) who makes the complaint in a legal action or proceeding