A person who has reached the pinnacle of whatever it is that can be, this person is beyond time space and existence as we know it. To be called this is confirmation that you are one of the most based individuals to ever exist.
A grumpy old man who can't be bothered with anything, has all his life been in a bad mood, and generally, has a dark cloud over his head.
You, Mr. Smith, are an old blusterfuck! You have been in a bad mood for forty years, can't be bothered with anything, and you steal my happiness every time you darken my door.