Definition - What does Friendly Witness mean?
A friendly witness is a witness in a court proceeding called by a party to testify in their favor. If the friendly witness testifies against the party who called them, that party can ask the judge to declare the witness as hostile.
Justipedia explains Friendly Witness
If a party calls a witness that they presume will testify in their favor or provide crucial facts relevant to the case that will tilt the jury in their favor, that witness is referred to as a friendly witness. Since the party calling the witness presumes that the witness will be testifying in their favor, that party is forbidden from cross examining him or her. The need for cross-examination can arise when the friendly witness says something that negatively affects the party’s cases. In such cases, the party generally asks the judge to declare the erstwhile friendly witness as a hostile witness.