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

Two of the claimants were complainants who gave evidence ​during Spacey's 2023 criminal trial in London, where ​the now 66-year-old actor was acquitted of all charges. —Reuters, NBC news, 19 Mar. 2026

The deputy chief magistrate, Tan Ikram, ordered that Partey is not to contact directly or indirectly this new complainant, in line with the bail conditions he was served previously. —James McNicholas, New York Times, 13 Mar. 2026

The complainant was the Campaign for Accountability, which argued that Halligan should face disciplinary action for her involvement in the federal prosecutions of former FBI Director James Comey and New York Attorney General Letitia James. —David Zimmermann, The Washington Examiner, 6 Mar. 2026

The ethics inquiry board deliberated on the motion to dismiss and held the motion in abeyance pending the complainant’s witnesses testifying. —Mary Divine, Twin Cities, 18 Feb. 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