One who frequents a pub or bar. Derived from the word 'regular'. The problem being one cannot be a true 'regular' if one is capable of saying 'regular'. Any true 'regular' will be a 'redderler'as they are too drunk to say the word any other way.
Bar Patron #1, "I've been drinking Big Feller in here for years. That's what makes me a redderler."