anesthetic

Definition of anesthetic
National Cancer Institute

anesthetic

(A-nes-THEH-tik)
A drug or other substance that causes a loss of feeling or awareness. Local anesthetics cause a loss of feeling in one small area of the body. Regional anesthetics cause a loss of feeling in a part of the body, such as an arm or leg. General anesthetics cause a loss of feeling and a complete loss of awareness that feels like a very deep sleep.

Source: NCI Dictionary of Cancer Terms