Translation guide
The English word "dumb" has several distinct meanings. This guide covers the most common uses for learners: inability to speak, temporary speechlessness, and informal use meaning "stupid."
Describing a person who cannot speak due to a physical or medical condition.
A common, neutral phrase meaning 'unable to speak.' It literally means 'mouth cannot function.'
彼は事故で口がきけなくなった。
He became unable to speak after the accident.
A noun meaning 'mute person.' Can be considered blunt or outdated; use with care.
This term can be perceived as insensitive or archaic. Prefer descriptive phrases like 口がきけない in most situations.
彼は生まれつきの唖だ。
He has been mute since birth.
Describing someone who is so shocked or surprised that they cannot speak.
Literally 'to lose words.' Used when someone is so shocked they cannot speak.
その知らせを聞いて、彼女は言葉を失った。
She was speechless when she heard the news.
To be dumbfounded or taken aback, often with a nuance of being stunned into silence.
突然の出来事に、みんなあっけにとられた。
Everyone was dumbfounded by the sudden event.
To be at a loss for words, to be speechless. Often used in formal or written contexts.
彼の無礼な態度に、私は絶句した。
I was speechless at his rude attitude.
Informal use meaning 'stupid' or 'foolish.'
The most common casual word for 'stupid' or 'idiot.' Can be used playfully or insultingly depending on tone.
Can be offensive if used aggressively. Use with close friends only.
そんなバカなこと言わないで。
Don't say such dumb things.
あいつは本当にバカだ。
That guy is really dumb.
Similar to バカ, but more common in Kansai dialect. Often used jokingly.
アホなこと言うな。
Don't say dumb stuff.
Means 'stupid' or 'foolish,' with a nuance of being slow or dim-witted. Less harsh than バカ.
A more formal or literary word for 'foolish' or 'stupid.' Often used in writing or serious contexts.
In Japanese, directly calling someone 'dumb' (バカ, アホ) is very casual and can be highly offensive. In polite or formal situations, use softer expressions like あまり賢くない (not very smart) or rephrase entirely.
彼はあまり賢くない。
He is not very smart.
Both mean 'stupid' or 'idiot,' but バカ is standard Japanese while アホ is strongly associated with the Kansai region. In Kansai, アホ can be more playful, while バカ might sound harsher. In Tokyo, バカ is the default.
He has a dumb look on his face.
That is a dumb decision.