ばか
baka
The Japanese phrase for "you're stupid" is ばか (baka).
ばか is an expression used to tell someone they lack intelligence. While often used as an insult meaning "stupid" or "idiot", it can also be used affectionately between close friends or lovers to mean "silly" or "foolish".
Is there a formal and an informal way to say it?
This is an informal expression. Because the subject "you" is often omitted in Japanese, simply saying ばか is a common way to imply "you are stupid".
How does it change in a sentence?
ばか can function as either a noun (an idiot) or an adjective (stupid) depending on the context and the particles used in a sentence.
How do you pronounce it?
baka
Did you know?
- The word ばか can be used as an intensifier meaning 'extremely' or 'absurdly' when describing a quantity, such as ばか高い for 'stupidly expensive'.
- In some contexts, ばか can be a compliment meaning someone is 'foolishly' dedicated to a craft or passion, such as a ばか for trains.
- In the Kanto region including Tokyo, ばか is a harsh insult, but in the Kansai region around Osaka, people prefer the word あほ to mean 'stupid'.
Examples in context
- お前馬鹿だよ。You're an idiot!
- 君は本当にばかだな。Kimi wa hontou ni baka da na.You are really stupid.
- そんなことも分からないなんて、ばかじゃないの？Sonna koto mo wakaranai nante, baka janai no?Aren't you stupid for not even knowing that?
- あいつは本当にばかな奴だ。Aitsu wa hontou ni baka na yatsu da.That guy is a truly stupid person.
Example conversation
Two siblings are arguing over a trivial mistake during a video game.
- 陽太 Yota陽葵、また間違えたの？Himari, mata machigaeta no?Himari, did you make a mistake again?
- 陽葵 Himariそんなこと言わないでよ！Sonna koto iwanaide yo!Don't say that!
- 陽太 Yota本当にばかなんだから。Hontou ni baka nanda kara.You are so stupid, seriously.
- 陽葵 Himariもう、陽太のバカ！Mou, Youta no baka!Ugh, you're the stupid one, Youta!
Sources
- Pronunciation: Wiktionary entry ばか, CC BY-SA 4.0, dump of 2026-09-26.
