bakana! バカな！

In Japanese, baka na バカな means something is "stupid."

But, often, b-b-b-bakana!!! translates to English as "impossible!!!" or "it can't be!!!" and it's typically used by villains when the protagonist does something extremely absurd that ruins all their plans.

Bakana! How can this be?! From the translation, the word bakana has literally nothing to do with "stupid." It means "impossible," for kamisama's sake! So what's going on here?

Manga: Yotsuba to! よつばと！ (Chapter 66, よつばとでんきや)

• Meaning

Meaning

The phrase baka na バカな means something "is stupid" because it's composed of two parts:

• baka
  バカ (also spelled 馬鹿.)
  Stupid.
  Idiot.
• na な, attributive copula.
  This is the "attributive form," rentaikei 連体形 of the da だ predicative copula, which would be shuushikei 終止形 instead.

This na な attributive copula replaces da だ when it comes before a noun, in a relative clause. Observe:

• kono hito wa baka da
  この人はバカだ
  This person is stupid.
• {baka na} hito
  バカな人
  A person [that] {is stupid}.
  A stupid person.
• {baka na} oniisan
  バカなお兄さん
  [My] older brother [who] {is stupid}.
  [My] stupid older brother.
• {baka na} imouto
  バカな妹
  [My] younger sister [who] {is stupid}.
  [My] stupid younger sister.
• {baka na} watashi
  バカな私
  Me, [who] {is stupid}.
  Stupid me.

The attributive form always comes before a noun, this means that the bakana!!! we hear in anime should come before something else, but it never does, so clearly it's a different thing, right?

Well, actually, no. It's the same thing. Except that what comes after bakana is cut short, left unsaid, so it sounds the grammar is different, when it's actually not.

What's cut short is probably this:

• baka na koto!
  バカなこと！
  Stupid thing! Stupid idea! Stupid action [you've taken]!
  Foolish!
  Non-sense!

Another part that's cut short is a demonstrative sonna そんな, "like that," before baka.

• sonna {baka na} koto!
  そんなバカなこと！
  Something [that] {is stupid} like that!
  Something stupid like that!
  Something that stupid!

We can already picture what's probably being said:

• sonna {baka na} koto aru wake ga nai!
  そんなバカなことあるわけがない！
  Something that stupid can't possibly exist!
• sonna {baka na} koto dekiru wake ga nai!!
  そんなバカなことできるわけがない！！
  Something that stupid can't possibly be done!!
• sonna {baka na} koto okoru hazu ga nai!!!
  そんなバカなこと起こるはずがない！！！
  Something that stupid would never happen!!!

Or something like that. You can replace stupid by absurd and then it probably makes more sense:

• There's no way something so absurd could possibly have happened!

Manga: Yotsuba to! よつばと！ (Chapter 66, よつばとでんきや)

• nanii!! sonna baka na!!
  なにィ！！そんなバカな！！
  Whaat!! [Something] that stupid [can't be]!!

By the way, since baka na! is cut short, it sometimes has a small tsu っ at the end of the phrase. That small tsu is purely phonetic and means nothing.

• baka na!
  バカな！
  No way!
  Impossible!
  It can't be!
• baka na'!
  バカなっ！
  (same meaning.)

Both sentences above mean the same thing.