noun
modern boy
1920s slang for a young Japanese man who adopted Western fashions, attitudes, and lifestyle, often seen as a counterpart to the 'modern girl' (モダンガール). Dated term, now mainly used in historical or cultural contexts.
See also: モダンガール
1920年代、東京の街には多くのモダンボーイがいた。
In the 1920s, there were many modern boys on the streets of Tokyo.
彼は当時、モダンボーイと呼ばれる若者たちの一人だった。
He was one of the young men called modern boys at that time.