Defence Mechanisms refer to strategies used by the ego to protect itself from threatening thoughts and feelings, especially anxiety created by the Id; strategies the ego uses to disguise or transform unconscious wishes.

It is a common pattern of behavior, usually an adaptive coping style when it occurs in moderation, observed in response to a particular situation. Psychoanalytic theory suggests that Defense mechanisms are unconscious processes originating in the ego. Moreover, Defence Mechanism is defined as largely unconscious reactions that protect a person from unpleasant emotions such as anxiety and guilt ; devices the ego uses to keep threatening material out of awareness and thereby reduce or avoid anxiety; strategies the ego uses to defend itself against the anxiety provoked by conflicts of everyday life; tactics that keep unacceptable thoughts, instincts, and feelings out of conscious awareness and thus protect the ego against anxiety Defense mechanisms involve denials or distortions of reality.