testify

UK: /ˈtɛstɪfaɪ/ US: /ˈtɛstəˌfaɪ/ ,(tes′tə fī′)

Inflections of 'testify' (v): (⇒ conjugate)

testifies

v 3rd person singular

testifying

v pres p

testified

v past

testified

v past p

WordReference Random House Learner's Dictionary of American English © 2025

tes•ti•fy /ˈtɛstəˌfaɪ/   v., -fied, -fy•ing. 

1. Law to state or declare under oath, usually in court: [no object]
   The witness was afraid to testify.
   [~ + (that) clause]
   testified that she had seen him fleeing from the scene of the crime.
2. to give or provide evidence about something:
   [~ + to + object] This excellent book testifies to the author's ability.

tes•ti•fi•er, n. [countable] See -test-.

WordReference Random House Unabridged Dictionary of American English © 2025

tes•ti•fy  (tes′tə fī′), v., -fied, -fy•ing. 
v.i. 

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.

v.t. 

4. to bear witness to;
   affirm as fact or truth;
   attest.
5. to give or afford evidence of in any manner.
6. Law to state or declare under oath or affirmation, usually in court.
7. to declare, profess, or acknowledge openly.

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

tes′ti•fi′er, n. 
Synonyms

• 5. indicate, show, signify, prove.

Collins Concise English Dictionary © HarperCollins Publishers::

testify / ˈtɛstɪˌfaɪ/ verb ( -fies, -fying, -fied)

1. (when tr, may take a clause as object) to state (something) formally as a declaration of fact
2. to declare or give (evidence) under oath, esp in court
3. when intr, often followed by to: to be evidence (of); serve as witness (to)
4. (transitive) to declare or acknowledge openly

Etymology: 14th Century: from Latin testificārī, from testis witness

ˌtestifiˈcation noun

ˈtestiˌfier noun