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

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

Fong declined to specify the nature of the allegations or identify complainants, beyond confirming that the accusations were unrelated to either Gomez or Henrich. —Pj Green, Kansas City Star, 16 Jan. 2026

The complainant alleged that Young yelled and became hostile before striking them in the chest with a closed fist while the vehicle was stopped. —Wbff Staff, Baltimore Sun, 13 Jan. 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