Psychological Terms — Anaesthetic 
An anaesthetic is any drug or agent that produces anaesthesia—meaning it reduces or eliminates sensation. Anaesthetics are used to prevent pain and awareness during medical procedures. They may induce complete unconsciousness (general anaesthetic) or numbness in a specific part of the body (local anaesthetic).
General anaesthetics affect the brain globally, preventing sensation and consciousness, while local anaesthetics block nerve transmission near the site of administration. The psychological relevance of anaesthetics includes their effects on consciousness, memory, and pain perception. Some individuals may respond differently based on tolerance, anxiety, or underlying psychological conditions.
The term also functions as an adjective describing anything that causes loss of feeling.