cannot contain one's anger; can't calm down
Idiomatic expression literally meaning 'the bug in one's stomach won't settle'; used when someone is so angry they cannot calm down. Often implies a sense of righteous indignation or frustration that persists.
I can't contain my anger at his rude attitude.
When I heard that excuse, I just couldn't calm down.
A more general and common expression for 'to get angry'. 腹の虫がおさまらない emphasizes the inability to suppress or calm the anger, often with a nuance of lingering frustration.
A shorter variant with the same meaning, omitting 腹の. Slightly less common but interchangeable.
Standard kana-mixed spelling; おさまらない is usually written in kana for this idiom.
Kanji spelling using 治 (calm, subside); less common but seen.
Kanji spelling using 納 (settle, be contained); rare and may be considered nonstandard.
From the folk belief that a 'bug' (虫) in the stomach controls emotions; when the bug is agitated, one cannot calm down. The exact origin is uncertain, but the expression is a traditional Japanese idiom.