godan verb (-ru), transitive verb
show bitterness; appear vexed; act resentful
Describes someone outwardly showing frustration, regret, or resentment, often through words or demeanor. The subject is typically a person reacting to an unfavorable outcome.
試合に負けて、彼は悔しがっていた。
He was showing his frustration after losing the match.
点数を間違えられて、
My younger sister is acting resentful because her score was recorded incorrectly.