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testify against someone or something

to be a witness against someone or something. Who will testify against him in court? I cannot testify against the company I work for.
See also: testify

testify for someone

to present evidence in favor of someone; to testify on someone's behalf. I agreed to testify for her at the trial. Max testified for Lefty, but they were both convicted.
See also: testify

testify to something

to swear to something. I will testify to your whereabouts if you wish. I think I know what happened, but I would not testify to it.
See also: testify

testify to

1. To make a statement based on personal knowledge in support of some asserted fact; bear witness to something: Many astronauts have testified to the thrill of weightlessness. The witness testified to the accuracy of the defendant's story.
2. To serve as evidence: The wreckage testifies to the strength of the storm.
See also: testify
References in periodicals archive ?
Although expert witnesses aren't required to testify from personal knowledge, they must be qualified to give opinions, the Supreme Court has said.
For example, an actuary may be called upon to testify as to the "human life value" of an individual in a wrongful death case or to the life expense for a teenager permanently disabled as the result of an at-fault accident.
Neither Lustgarten nor his attorney appeared at the revocation hearing because the neurosurgeon says he was subpoenaed to testify in Miami-Dade County, Fla.
Experts, by definition, are the only witnesses permitted to testify about their opinions, and their opinions carry substantial weight.
Vogel has said that he is willing to testify before a congressional committee if he is subpoenaed to do so.
There are authorities who assess wine collections, testify in dance accidents, analyze bird feathers for toxic contamination, evaluate swimming pools, consult on "swine management,' and otherwise report on things that can bend, break, explode, or make people sick.
Koppel said the marriage was ``moribund'' given the couple's lengthy separation with little to no contact and ordered the woman to testify.
This article examines the government's duty to provide information relating to personnel and disciplinary matters concerning law enforcement officers who will testify on the government's behalf.
Police officers receive training to testify as witnesses, and they garner a certain professional respect in that role through on-the-job experience.
Lewis Reid, former president and CEO of The California Endowment, will testify that the Premera conversion serves the public interest.
The 2nd District Court of Appeal rejected Jaymar Dodds' claim that the judge erred when he denied Dodd's request in the middle of trial for a delay because his fiancee became ill and couldn't testify that he was with her when one of the robberies occurred.
If the department supports the bill, the sponsor may have suggestions for the officers who will testify.
As part of the case settlement, Lewis agreed to testify against Zomalt and Munassar.
As part of the settlement, Lewis agreed to testify against Zomalt and Munassar, Foltz said.