Privilege entitles a party (or their successor in title) to withhold evidence from production to a third party or the court. There are various forms of privilege, including:
Another form of privilege is without prejudice privilege, which generally prevents statements made in a genuine attempt to settle an existing dispute, whether made in writing or orally, from being put before the court as evidence of admissions against the interests of the party which made them. See Practice note, Without prejudice privilege: an overview.