bottled-up frustration

Translations
сдерживаемое разочарование
His bottled-up frustration was evident in his harsh words.
Его сдерживаемое разочарование было очевидно в его резких словах.
Definitions
Bottled-up frustration refers to feelings of anger, annoyance, or irritation that a person keeps hidden or suppressed instead of expressing them openly. Over time, these unexpressed emotions can build up and may eventually lead to emotional outbursts or stress.
Words
frustration

noun
разочарование