悔くやしん坊ぼう

noun

spiteful person; sore loser

Refers to someone who is easily frustrated or resentful when things don't go their way, often used for children or in a mildly teasing manner.

• 弟おとうとは負まけるとすぐ泣なく悔くやしん坊ぼうだ。

  My little brother is a sore loser who cries as soon as he loses.

• あの子こは悔くやしん坊ぼうで、ゲームに負まけると拗すねてしまう。

  That kid is a spiteful one; he sulks whenever he loses a game.