Libido is what earlier psychologists called "will" or "tendency."
Libido can perhaps be described as "effect," or "capacity for effect."
Libido is an expression taken from the theory of the emotions.
Libido: Life-force, élan vital, or (restricted) the energy of the sex-instinct.
On the opposite page Pudicitia—in a very spirited attitude—is driving her spear through the throat ...