Unconscious strategies that the ego uses to manage the conflict between the ID and the Super Ego.
Repression:
Burying an unpleasant thought or desire in the unconscious.
For example, traumatic childhood experiences so that they are forgotten.
Displacement:
Emotions are directed away from their source or target, towards other things.
For example, wringing a dishcloth in anger, which would have otherwise been directed at the cat scratching the furniture.
Denial:
A threatening thought is ignored or treated as if it were not true.
For example, a wife might find evidence that her husband is cheating on her, but explain it using other reasons.