noun, noun which may take the genitive case particle 'no'
youthful ardor; rash impulse of youth
Describes the passionate but often reckless enthusiasm of young people. Somewhat literary and not an everyday word; compare 年少客気 (ねんしょうかっき) for a similar concept.
See also: 年少客気
Driven by youthful ardor, I ended up making a reckless plan.
彼の行動は青年客気のなせるわざだった。
His actions were the result of a rash impulse of youth.
Very similar in meaning; 年少客気 emphasizes the inexperience of youth, while 青年客気 focuses more on the passionate drive.
Compound of 青年 (youth) and 客気 (rashness, youthful vigor). The exact historical derivation is uncertain, but the combination is conventional for expressing youthful impetuosity.