A term commonly used by Sigmund Freud that refers to the psychic (sexual) energy invested in any particular mental formation.
"The psychic energy, cathexis, processing itself as an executive force, is formidable. The reserves of intelligence are the different parts of the Being and are denominated as bound cathexis or psychic energy in a potential and static state. The bound cathexis orients us in the work related with the disintegration of the ego and with the liberation of the mind. The bound cathexis, contained within the mind, guides us in the work related with Revolutionary Psychology and with Integral Revolution. The values of the Being constitute the bound cathexis. Only the bound cathexis can liberate the mind through the disintegration of the undesirable psychic elements which have been segregated by means of structural and transactional analysis. Bound cathexis is different from loose cathexis, since the latter is the psychic energy which the ego utilizes to dominate the mind and the body for its manifestation. We have to permit the bound cathexis (which is the dynamic psychic energy) to be the one to direct our existence. We have to work psychologically in order for the bound cathexis to enter into activity to dominate and govern the free cathexis. This free cathexis is the energy of the body which has always been pitifully dominated by the loose cathexis, which is the ego." - Samael Aun Weor, The Revolution of the Dialectic