Libido History of the concept 

Sigmund Freud popularized the term & defined libido as the instinct energy or force, contained in what Freud called the id, the largely unconscious structure of the psyche. Building on the work of Karl Abraham, Freud developed the idea of a series of developmental phases in which the libido fixates on different erogenous zones—first in the oral stage , then in the anal stage , then in the phallic stage, through a latency stage in which the libido is dormant, to its reemergence at puberty in the genital stage. Freud pointed out that these libidinal drives could conflict with the conventions of civilized behavior, represented in the psyche by the superego. It is this need to conform to society & control the libido that leads to tension & disturbance in the individual, prompting the use of ego defenses to dissipate the psychic energy of these unmet & mostly unconscious needs into other forms. Excessive use of ego defenses results in neurosis. A primary goal of psychoanalysis is to bring the drives of the id into consciousness, allowing them to be met directly & thus reducing the patient's reliance on ego defenses.

Freud viewed libido as passing through a series of developmental stages within the individual. Failure to adequately adapt to the demands of these different stages could result in libidinal energy becoming 'dammed up' or fixated in these stages, producing certain pathological character traits in adulthood. Thus the psychopathologized individual for Freud was an immature individual, & the goal of psychoanalysis was to bring these fixations to conscious awareness so that the libido energy would be freed up & available for conscious use in some sort of constructive sublimation.

According to Swiss psychiatrist Carl Gustav Jung, the libido is identified as psychic energy. Duality that creates the energy of the psyche, which Jung asserts expresses itself only through symbols - 'It is the energy that manifests itself in the life process & is perceived subjectively as striving & desire.'

Defined more narrowly, libido also refers to an individual's urge to engage in sexual activity. In this sense, the antonym of libido is destrudo.

More recently, philosopher & psychologist James Giles has argued that human sexual desire is neither a biological instinct nor something learned or constructed by culture. Rather it is an existential need based on the awareness of having a gender. Having a gender creates a sense of incompleteness. We then seek to fill this incompleteness through the baring & caressing of the desired gender.