reaction formation
in psychoanalytic theory, a defense mechanism in which unacceptable or threatening unconscious impulses are denied and are replaced in consciousness with their opposite. For example, to conceal an unconscious prejudice, an individual may preach tolerance; to deny feelings of rejection, a mother may be overindulgent toward her child. Through the symbolic relationship between the unconscious wish and its opposite, the outward behavior provides a disguised outlet for the tendencies it seems to oppose.