noun
popular person; star; favorite
Rare term for a person who is currently popular or in vogue; can refer to a celebrity, a favorite child, or anyone enjoying a moment of popularity.
あの子はクラスの流行りっ子だ。
That kid is the popular one in the class.
彼女は今、町の流行りっ
She's the town's star right now, and everyone copies her.
noun
popular geisha
Historical term for a geisha who was particularly popular or in demand. Also written 流行っ妓 or 流行りっ妓. Very rare in modern usage.
江戸時代、彼女は吉原で一番の流行りっ子だった。
In the Edo period, she was the most popular geisha in Yoshiwara.
Compound of 流行り (はやり, 'popularity, fashion') + っ子 (っこ, a suffix indicating a person with a certain characteristic). The suffix っ子 is a colloquial variant of 子 (こ).