testify against

testify against (someone or something)

To present evidence or testimony against someone or something as a witness in a trial. I refused to testify against the mob boss unless the police were able to guarantee the safety of my family. Spouses cannot be made to testify against one another.See also: testify

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