Definition of It girl in English:

It girl

noun

informal
  • A young woman who has achieved celebrity because of her socialite lifestyle.

    • ‘Here's the it girl Sarah Jessica Parker in 2003, and here are Josh Holloway and Clay Aiken just this year.’
    • ‘From one of today's it girls to a ‘60s icon, we're getting groovy, baby, with ‘Mod Squad’ groovy chick Peggy Lipton.’
    • ‘Although Cleo is not born a society woman, she aspires to that status and competes with the other women in the novel to be the it girl.’
    • ‘While Essence's assemblage of it girls presented a slew of fabulous black women, it did not challenge the foundation of exclusivity, privilege, and color prerequisites.’
    • ‘She was muse, artist, lover and it girl.’

Origin

Coined by the American screenwriter Elinor Glyn (1864–1943) with reference to the American actress and sex symbol Clara Bow, who made her name in such films as It (1927). The current use dates from the 1960s.