This document discusses Sigmund Freud's concept of defence mechanisms, which are unconscious processes that protect a person's ego from anxiety, shame, loss of self-esteem or other uncomfortable feelings. Defence mechanisms operate at an unconscious level to resolve internal conflicts and reduce stress. They are classified as either positive or negative based on their effects. Positive mechanisms include compensation, sublimation and rationalization, while negative ones involve suppression, projection and fantasy. The document provides examples to illustrate common defence mechanisms.