noun
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.
彼は村一番の壮士として知られていた。
He was known as the finest young man in the village.
酒場に数人の壮士が入ってきて、にぎやかになった。
Several swaggering young men came into the bar and livened it up.