A party that the court feels is hostile against the party they are supposed to testify for. They can be cross examined if they are called. They can be impeached by their own credibility.
Polarize is to force a something or someone to go in only one direction, or to cause people to divide into two very distinct groups. 1  When a special microscope forces the transverse waves created by a light to be focused only in one direction, this is an example of when it polarizes. When a political leader pits one group of people in society against another using inflammatory speech, this is an example of when he polarizes the groups.
To polarize is to divide. Something that's been polarized has been split into two sides that are so different, it seems as though they're from opposite ends of the earth â like the North Pole and the South Pole. Political parties have long been polarized by different views and approaches to government.