1. Somebody who is obviously lying, posturing, idly boasting, who does not have the goods; one who is 'so full of shit' that it would take four flushes during the movement to clear the bowl.
Originally from game of poker, c.1880, one who bluffs that they have five cards in a flush when they only hold four.
Steve: Phil doesn't really have a summer house?
Bob: No, he's living with his parents. He's a lying, four-flushing sack of shit.
a person who makes false or pretentious claims; bluffer
Jane thinks she has everything, but all she is is a four flusher.