In governments, immunity is a protection from law suits granted to certain political authorities. For example, in Turkey, members of parliament cannot be sued. This is known as parliamentary immunity, or legislative immunity.
In law, immunity is an exemption from civil or criminal liability. For example, a witness may agree to testify against others in exchange for a grant of immunity from prosecution.
In biology, immunity is the ability of an organism to resist a particular disease by the action of specific antibodies or sensitized white blood cells.