LIBIDO

The word "libido" in Latin means "desire, longing, fancy, lust, or rut." Although the adjective "libidinous" meaning lustful has been used in English for 500 or so years, "libido" made a belated entry into the English language in1913, thanks to Sigmund Freud and other psychoanalysts who applied the term to psychic energy or drive, especially the sexual instinct.