Retard. It's original definition was '...to cause a functioning system to temporarily become non-functional, as in ...'
'to retard the spark in a sparkplug'. Then it was used to describe developmentally disabled (differently-abled) persons. Then, THAT was deemed offensive, so a person can get into trouble calling someone retarded, which I do all the time lately. But I'm using the original definition of the word, because I have faith that people are only being douchebags, temporarily. My argument is that if the 2ndary meaning of the word is no longer used, I should be free to use the original definition of the word. I think 'retarded' exactly identifies someone one has known for decades who obviously is temporarily not functioning. The hope is that the word will 'spark' them into getting their head out of their ass.