affidavit

American  

[af-i-dey-vit] / ˌæf ɪˈdeɪ vɪt /

noun

Law.

1. a written declaration upon oath made before an authorized official.

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affidavit British  

/ ˌæfɪˈdeɪvɪt /

noun

1. law a declaration in writing made upon oath before a person authorized to administer oaths, esp for use as evidence in court

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Other Word Forms

• preaffidavit noun

Etymology

Origin of affidavit

First recorded in 1615–25; from Medieval Latin affīdāvit “(he) has declared on oath,” 3rd-person singular perfect of affīdāre “to declare an oath”; affiance

Explanation

If you make a written statement to the police or another recognized authority like a notary public that you swear is the truth, the whole truth, and nothing but the truth, what you've put down on paper is an affidavit. We get the noun affidavit from the Latin affidare, which means "to pledge." When you state something in an affidavit, you're pledging to the powers that be that you're not lying. The word usually appears in legal settings; if you watch a lot of cop shows or courtroom dramas, it probably rings a bell. "According to the affidavit, Mrs. Smith told police she found the burglar in her closet wearing her most expensive pair of shoes."

Example Sentences

The state also pointed to later postconviction filings and defense counsel’s own affidavit suggesting that she had not in fact preserved the fuller pretext theories subsequently pressed on appeal.

From Slate • Apr. 10, 2026

Hatley said no to both questions but showed the highest level of deception in both answers, according to an affidavit that Stafford later filed.

From Slate • Apr. 6, 2026

The affidavit also detailed a police interview with Busfield in which he suggested that the boys’ mother might have sought “revenge” on the director for “not bringing her kids back for the final season.”

From Los Angeles Times • Apr. 6, 2026

During an interview at the scene of the crash, Woods was "sweating profusely" and his movements were "lethargic and slow", an officer wrote in the arrest affidavit released on Tuesday.

From BBC • Mar. 31, 2026

The group, which was headed by Walter Sisulu and Duma Nokwe, traveled on the only airline that would accept such an affidavit: the Israeli airline, El Al.

From "Long Walk to Freedom" by Nelson Mandela

Related Words

• oath
• testimony