Translation guide
The English word "stupid" covers a wide range of meanings from low intelligence to foolish actions, annoying things, and even informal intensifiers. Japanese has many words for these nuances, but direct translations can sound harsh or unnatural. This guide organizes the most useful Japanese expressions by the intended English meaning.
Describing someone who is not smart, slow-witted, or unintelligent.
The most common and versatile word for 'stupid' or 'fool'. Can be used as a noun or adjective. Mildly insulting; can be playful among close friends.
He is stupid.
Don't say stupid things.
Kansai dialect equivalent of 馬鹿, but widely understood. Often sounds softer or more humorous than 馬鹿 in standard Japanese.
That guy is stupid, isn't he? (Kansai dialect)
More formal and literary word for 'foolish' or 'stupid'. Often used in writing or serious contexts.
That is a foolish decision.
Means 'stupid' in the sense of being slow, dim-witted, or a blockhead. Often implies a lack of common sense.
He has a stupid look on his face.
Describing an action, idea, or decision that is unwise, senseless, or shows poor judgment.
Adjective meaning 'absurd', 'ridiculous', or 'stupid'. Used for actions or ideas that are clearly foolish.
That's a stupid idea.
Don't ask stupid questions.
Common phrase meaning 'to do something stupid'. Versatile and natural in conversation.
I did something stupid again.
As above, but used for actions/decisions. Formal tone.
Means 'trivial', 'worthless', or 'stupid' in the sense of being pointless or silly. Often used for jokes, ideas, or things that waste time.
Expressing frustration that something is irritating, troublesome, or not working properly. Often used as 'This stupid thing!'
Can be used attributively to mean 'damn' or 'stupid' for inanimate objects causing frustration.
This stupid machine broke again.
Means 'unpleasant' or 'disagreeable'. A softer way to express annoyance without strong insult.
Stupid weather, huh.
Slang for 'pissed off' or 'annoying'. Used when something makes you angry or frustrated.
Using 'stupid' informally to mean 'very' or 'extremely', e.g., 'stupid hot', 'stupid expensive'.
Common colloquial intensifier meaning 'ridiculously' or 'insanely'. Works for both positive and negative adjectives.
It's stupid hot today.
That car is stupid expensive.
Standard intensifier meaning 'very' or 'really'. Less emphatic than めちゃくちゃ but more neutral.
It's stupid cold, isn't it?
Prefix meaning 'absurdly' or 'stupidly'. Can be used with some adjectives, but less common and can sound rough.
Not as flexible as English 'stupid + adjective'. Often limited to set phrases like バカ高い (stupid expensive) or バカでかい (stupid huge).
stupidly high rent
Being so in love that you act foolishly or can't think straight. E.g., 'I'm stupid in love.'
Proverb meaning 'love is blind'. Captures the idea of being stupid because of love.
They say love is blind, you know.
To be infatuated or carried away with love, often acting foolishly.
To be giddy or light-headed with love, making one act silly.
Pretending not to know or understand something.
To play dumb, feign ignorance. Very common in conversation.
Don't play stupid.
He played stupid even though he knew.
To feign innocence, especially when accused of something. Stronger nuance of denying knowledge.
To pretend not to know or notice; to ignore deliberately.
Calling someone 馬鹿 directly to their face is a strong insult and can cause serious offense. Use with caution, and only among very close friends in jest. In formal or polite situations, avoid any direct 'stupid' labels.
Are you stupid? (very rude)
In standard Japanese, 馬鹿 is the default word for 'stupid'. アホ is strongly associated with the Kansai region (Osaka, Kyoto, etc.) and can sound softer or more humorous to standard Japanese speakers. However, in Kansai, アホ is the normal word and 馬鹿 can sound harsher. Be aware of regional differences.
Instead of directly calling someone stupid, Japanese often uses phrases like ちょっと考えが足りない (a bit lacking in thought) or あまり賢くない (not very smart). This is more polite and indirect.
That was a stupid mistake.
I feel stupid for believing him.
This stupid phone won't work!
It's a stupid act.
くだらないことで悩むな。
Don't worry about stupid things.
このパソコン、むかつく！
This stupid computer is pissing me off!
He's stupid in love with her.
She's so stupid in love she can't focus on anything.
彼は白を切ったが、証拠がある。
He played stupid, but we have evidence.
She played stupid and ignored me even though she saw me.