言語道断

ごん　ご　どう　だん
gon go dou dan

Today on "The Occasional Yo-ji" we have a failure of language. Literally. The kanji could be translated as "the failure of the methods of language."

Definition: とんでもないこと、言うにたえないこと。
Translations:
(Rikai-chan gives)
1. Preposterous
2. Inexcusable
3. Offensive to a point that defies encapsulation in words

I learned this one and had the opportunity to use it almost immediately. I was told that this is what you say to someone who does something really bad, when they violate one of the するわけにはいかない rules. When they do something that's forbidden based on societal rules... something that a person KNOWS that they shouldn't do, and yet they do it anyway. When I learned the するわけには行かない construction, Nirav's example was: クラスの前に先生の間違えを正すわけには行かない。 You don't correct the teacher's mistakes in front of the class. That may be true, especially here, but it's not quite so severe a situation that you'd say 言語道断. The lucky opportunity I stumbled across was this one: クラスの前に先生の顔を殴るわけには行かない。 You don't punch your teacher in the face in front of the class. THAT'S 言語道断 right there.

It was in the middle of kyuushoku with an elementary school student, and man, I could've understood it or forgiven it, if it had been during like, rough-housing time (2:30-3:15). But he was eating, I was eating... across the room. He got up, walked over to where I was sitting, looked at me, and then punched me, close-fisted square in the face.

In his defense, he is a first-grader.
In my defense, I've seen my co-workers at middle-school get punched in the face too many times to let that kind of behavior go un-yelled at.

例文：あんたのお嫁さんが病院で赤ちゃんを生んでいる。あんたはバカ外人と暴飲している。それは言語道断！
You! Your wife is at the hospital, birthing a baby. You're getting wasted with your idiot gaijin friends! That's inexcusable!
(Another real life example)