testify

American  

[tes-tuh-fahy] / ˈtɛs təˌfaɪ /

verb (used without object)

testified, testifying

1. to bear witness; give or afford evidence.

2. Law. to give testimony under oath or solemn affirmation, usually in court.

3. to make solemn declaration.

---

verb (used with object)

testified, testifying

1. to bear witness to; affirm as fact or truth; attest.

2. to give or afford evidence of in any manner.

   Synonyms:

   prove, signify, show, indicate

3. Law. to state or declare under oath or affirmation, usually in court.

4. to declare, profess, or acknowledge openly.

testify British  

/ ˈtɛstɪˌfaɪ /

verb

1. (when tr, may take a clause as object) to state (something) formally as a declaration of fact

   I testify that I know nothing about him

2. law to declare or give (evidence) under oath, esp in court

3. to be evidence (of); serve as witness (to)

   the money testified to his good faith

4. (tr) to declare or acknowledge openly

---

Other Word Forms

• pretestify verb (used with object)
• retestify verb
• testification noun
• testifier noun
• untestifying adjective

Etymology

Origin of testify

1350–1400; Middle English testifyen < Latin testificārī to bear witness, equivalent to testi ( s ) witness + -ficārī -fy

Explanation

To testify is to make a statement or provide evidence, usually in court. Witnesses testify for the prosecution or defense. If you've ever seen a TV show about lawyers, you've probably seen someone testifying: putting their hand on the Bible, sitting in the witness seat, and telling what they know about a case. Testifying is serious business, but it doesn't always happen in court: If someone knows you're good at math, they can testify to your math skills. Or if you've been to a restaurant, you can testify to your friends that it has awesome desserts.

Example Sentences

Mountbatten-Windsor, who has faced his own calls to testify for a congressional inquiry, has denied any wrongdoing from his links to Epstein.

From BBC • Apr. 10, 2026

"She must come in to testify immediately, and if she defies the subpoena, we will begin contempt charges," he wrote in a statement.

From BBC • Apr. 8, 2026

More than 75 witnesses and about 20 experts are to testify during the proceedings, which are due to run through April.

From Barron's • Apr. 7, 2026

Witnesses flew from Brazil to testify that his ex-girlfriend, 24-year-old Ana Claudia Dos Santos, went missing in Brazil after breaking up with him.

From Los Angeles Times • Apr. 4, 2026

“He fled in the night. Must have guessed that your father would testify about his poaching attempt.”

From "Tiger Boy" by Mitali Perkins

Related Words

• announce
• argue
• assert
• declare
• depose
• indicate
• swear