adverse witness(n = noun.person) hostile witness - a witness whose relationship to the opposing party is such that his or her testimony may be prejudiced against the opposing party; "a hostile witness can be asked leading questions and cross-examined"
is a kind of witness
adverse, adverse opinion, bear witness, bear witness against, bearing false witness, character witness, expert witness, false witness, hostile witness, jehovah's witness, lay witness, material witness, witness, witness box, witness stand