a young woman with sex appeal and a magnetic personality.
2.
an extremely popular and attractive young socialite or celebrity.
Also, it girl.
Origin
nickname given to the sex symbol Clara Bow, subject of the 1927 novel and movie It, written by Elinor Glyn, who popularized the concept of it1 in the slang sense of ‘sex appeal’
British Dictionary definitions for It girl
It girl
noun
1.
a rich, usually attractive, young woman who spends most of her time shopping or socializing
Word Origin
C20: from it, in the sense: sex appeal
Contemporary definitions for It girl
noun
a young woman who has achieved celebrity status due to her social activities and lifestyle