Repression: Id impulses that threaten the Ego are pushed out of awareness and into the unconscious mind. This occurs without knowledge or awareness and is the most common and pervasive of all the defense mechanisms.

Regression: When anxiety becomes too intense an individual may revert to a developmentally earlier mode of functioning where they felt secure. In an extreme example a person might go into a corner and curl up in a fetal position.

Displacement: Shifting unacceptable feelings and desires from one object to a safer object.

Reaction Formation: Defending against an impulse by emphasizing and strongly embracing its opposite.

Projection: Attributing unacceptable Ego wishes, impulses and/or shortcoming to other people as a means to avoid dealing with them as internal threats.

Rationalization: When the Ego finds an "acceptable" reason for some unacceptable behavior, impulse or event that would otherwise threaten it.

Intellectualization: This is actually just a cognitively elaborate and sophisticated form of rationalization.

Denial: A newer term indicating a refusal to face some accept of self or reality that is threatening. The actual defense mechanisms at work are typically repression and/or rationalization.

Supression: Consciously pushing thoughts out of awareness so that one is not troubled by them. Because this is a conscious act it is not a classic defense mechanism.

Sublimation: Channeling socially distasteful or unacceptable impulses into socially acceptable courses of action. Exhibitionistic needs, for example, may be sublimated through an acting career.