A Knacker Flap is the large flap of skin prevailing from the gut that hangs over a males genitals, making them completely invisible when naked. The sighting of a Knacker Flap usually occurs in older obese men, and is usually tucked into their shirt. It is the male version of the "gunt" which is that of a female Knacker Flap.
Holy shit, that dude's got a mean Knacker Flap!
Omg is that guy naked? Where's his privates? Oh they're underneath his Knacker Flap.
Omg is that guy naked? Where's his privates? Oh they're underneath his Knacker Flap.
by purplejane September 08, 2014