young man in his prime; swaggerer; ruffian
Refers to a vigorous young man, often with a nuance of boldness or rough manners. Can carry a slightly old-fashioned or literary tone.
He was known as the finest young man in the village.
Several swaggering young men came into the bar and livened it up.
Composed of 壮 (vigorous, robust) and 士 (man, warrior). The exact historical derivation is uncertain, but the word conventionally refers to a man in his prime with a bold or rough character.