From The Art and Popular Culture Encyclopedia
A nymphet is a sexualized adolescent girl in the early days of puberty. The term was coined by Vladimir Nabokov in the novel Lolita, in which the main character, a self-described "nympholept", uses it to describe the girls (aged 9 to 14) to whom he was attracted.
The archetypal nymphet is the character Lolita of Vladimir Nabokov's novel, from which the term originated. Lolita has been filmed twice: the first adaptation was made in 1962 by Stanley Kubrick, and starred James Mason, Shelley Winters, Peter Sellers and, as Lolita, Sue Lyon; and in 1997 starring Jeremy Irons and Dominique Swain.
Nabokov describes these nymphets as being "deadly little demons" with feline features and thin, downy limbs. Nymphets are not always the type of girls a normal man would consider the prettiest, but they have a demonic ability to attract men at least ten years older than themselves.
The term faunlet, also coined by Nabokov and used by the character of Humbert Humbert, is used to describe the young male counterpart of a nymphet, in the same way that the mythological fauns (or satyrs) were the counterpart of the nymphs.
Nabokov borrowed the term nympholept, a rare, archaic term meaning a person seized by emotional frenzy, as if enchanted by nymphs. The word is found with this meaning in the poetry of Lord Byron: "The nympholepsy of some fond despair."
Nabokov used the word to describe one who could "discern" nymphets from other girls. In Humbert's own words: "[A nympholept is] an artist and a madman, a creature of infinite melancholy with a bubble of hot poison in [his] loins and a super-voluptuous flame permanently aglow in [his] subtle spine."