ichidan verb, intransitive verb
sulk; become sulky; act out of pique
Describes a petulant, disgruntled attitude where someone becomes uncooperative or irresponsible because they are upset. Often used for childish or immature behavior.
注意したら、弟はふてくされて部屋に閉じこもった。
When I scolded him, my younger brother sulked and shut himself in his room.
彼は仕事がうまくいかず、ふてくされて何もしなくなった。
Things weren't going well at work, so he got sulky and stopped doing anything.