Didn’t someone already ask that? “X” shorthand. It’d be easier to type out “Christ” than…that.
Nah. None of those end in an exclamation point. pizzabrat’s suggestion is for two characters, not one.
(I do like the Christ factorial idea. Talk about the eternal word!)
It doesn’t need an exclamation point - the exclamation point just served as context for my initial example. In fact, I imagine “X” used naked most of the time, for understatement, or just mild shock.