testify

1 of 2

verb

tes·​ti·​fy ˈte-stə-ˌfī 

testified; testifying

intransitive verb

1

: to make a solemn declaration under oath for the purpose of establishing a fact (as in a court)

2

a

: to make a statement based on personal knowledge or belief : bear witness

b

: to serve as evidence or proof

3

: to express a personal conviction

transitive verb

1

a

: to bear witness to : attest

b

: to serve as evidence of : prove

2

: to declare under oath before a tribunal or officially constituted public body

3

archaic

a

: to make known (a personal conviction)

b

: to give evidence of : show

testifier

ˈte-stə-ˌfī(-ə)r 

noun

testifier

2 of 2

noun

tes·​ti·​fi·​er ˈtestəˌfī(ə)r 

-īə

plural -s

: one that testifies : witness

especially : a religious proselyte

Synonyms of testify

Verb

• swear
• witness
• attest
• verify

Examples of testify in a Sentence

Verb

She refused to testify about who had given her the information.

She testified before Congress today.

He agreed to testify against his drug dealer.

He testified that he'd seen two people leave the building on the night of the murder.

These statistics testify that the program is working.

Several people testified during the revival meeting.

Recent Examples on the Web

Verb

Noncitizens have testified about similar conditions at supposedly temporary ICE detention facilities around the country. — Michael Loria, USA Today, 24 June 2026

Prior to Blankenship, former county payroll administrator Laura Baxter testified to confirm what Gillespie said during his testimony. — Lillie Davidson, Fort Worth Star-Telegram, 24 June 2026

This was among several first responders who have testified in this case. — Tara Lynch, CBS News, 24 June 2026

Gates testified on his relationship with Epstein on June 10 before the House Oversight and Government Reform Committee. — Emily Hallas, The Washington Examiner, 24 June 2026

Word History

Etymology

Verb

Middle English testifien, from Anglo-French testifier, from Latin testificari, from testis witness

First Known Use

Verb

14th century, in the meaning defined at intransitive sense 2a

Phrases Containing testify

• testify for the defense/prosecution

Rhymes for testify

• abscissae
• adonai
• alibi
• alkali
• alumni
• amoebae
• amplify
• annuli
• beautify
• brachii
• butterfly
• calculi

Kids Definition

testify

verb

tes·​ti·​fy ˈtes-tə-ˌfī 

testified; testifying

1

a

: to make a statement based on personal knowledge or belief

could testify to the student's devotion to her studies

b

: to make a formal statement of what one swears is true

testified in court

2

: to give outward proof : serve as a sign of

yawns testifying to fatigue

testifier

-ˌfī(-ə)r 

noun

Legal Definition

testify

verb

tes·​ti·​fy ˈtes-tə-ˌfī 

testified; testifying

intransitive verb

: to make a solemn declaration under oath or affirmation for the purpose of establishing a fact : give testimony

transitive verb

: to declare in testimony

testifier noun

Etymology

Verb

Latin testificari, from testis witness