I've been reading a fantastic book called Only Beautiful, Please. This is not about the dress code at Inky Fool Mansions, instead it's about life in North Korea*. I was rather struck by a linguistic point that the author makes about the North Korean term for Americans.
Americans are routinely described as "American Imperialist Bastards," shortened in Korean to michenom. But this word had been used so often that by now it has all but lost its initial venom. A Korean friend once smilingly told me that she had worked with American Imperialist Bastards during the time of the Agreed Framework and found they were very friendly, very generous people. She hoped they would come back, she said.
This seems to be the most extreme case I've ever heard of a term losing all meaning, and I suppose that it could only happen in a state where vocabulary can get you locked up. I rather enjoy it when a rude phrase has lost all meaning to the speaker. I always snigger quietly when a respectable and polite American tells me that something sucks.
*Though North Korea and my flat do have some things in common: a furiously enforced cult of personality and a paranoid fear of our neighbours.