noun, noun which may take the genitive case particle 'no'
young and hot-blooded; impetuous youth
Describes the passionate, impulsive nature of young people. Often used in literary or formal contexts.
少壮血気の若者たちが新しい事業に挑んだ。
The young and hot-blooded youths took on a new venture.
彼の少壮血気な行動が周囲を驚かせた。
His impetuous, youthful behavior surprised those around him.
A four-character compound (yojijukugo) combining 少壮 (young and vigorous) and 血気 (blood and spirit, i.e., hot-bloodedness). The exact historical origin is uncertain, but it follows a common pattern of pairing related concepts to create a literary expression.