bright young thing

Mr. Faggus gave his mare a wink, and she walked demurely after him, a bright young thing, flowing over with life, yet dropping her soul to a higher one, and led by love to anything; as the manner is of females.

A set of youngsters from entitled backgrounds sharing a strong desire to buck against convention, the Bright Young Things included the children of some of the oldest and wealthiest families in England (some of whom still appear in gossip magazines today: the Guinnesses, the Mitfords, the Tenants).