a. [ L. immunis. See Immunity. ] 1. Exempt; protected. -- Im*mu"nize v. t. [1913 Webster]

2. (Med.) Protected from disease due to the action of the immune system, especially by having been inoculated against or previously exposed to a disease. [PJC]

3. (Med.) Of or pertaining to the immune system or the components of the immune system. [PJC]

4. Not responsive; as, immune to suggestion. [PJC]

n. One who is immune; esp., a person who is immune from a disease by reason of previous affection with the disease or inoculation. [ Webster 1913 Suppl. ]

n. (Biol.) The complex of cells, cellular processes, and substances within and diffused throughout an organism which allow the organism to counteract or destroy noxious foreign substances introduced into the body, destroy infectious agents such as bacteria and viruses, destroy malignant cells, and remove cellular debris, thus protecting the organism against many of the potentially harmful external agents and internal events that could lead to sickness or death. The system has numerous interacting components, including circulating antibodies, antibody-producing cells, white blood cells and lymphokines, lymph tissue and lymph nodes, and stem cells which may differentiate into other types of cell, together with the thymus and spleen. The system is responsible for the phenomenon of immunity{ 3 }. See also immunoglobulin and antibody. [ PJC ]

adj. (Med.) Not having immunity; susceptible; likely to be affected with, if exposed.
Syn. -- liable to(predicate), nonresistant, unresistant, susceptible to(predicate). [ WordNet 1.5 ]