A word that’s blurted out when you are extremely upset, aggravated, or in pain and your brain can’t decide if you want to scream “fuck” or “shit”, so you end up with a combination of both and the result is “Fach.”
Fach! I stubbed my damn toe!
Person 1: “Hey you left your windows rolled down and it’s been pouring rain out for the past hour.”
Person 2: “FACH!!”