When the arm is hanging straight down and skin and fat from the bicep area drape down over the elbow and onto the forearm. Almost always seen on morbidly obese women but is not gender exclusive.
Look at all that extra skin draping down, she has a LOT of arm flap.
by Darth Nick March 18, 2004
Excessive arm skin or arm fat that hangs down when arms are raised up
That fat torta is flapping her arms like a chicken so she can hit him with her arm flap
by iintentx66 July 2, 2017
Someone who`s arms flap around like a bird while running or their arms flop around like noodles.
"What is that kid doing out there?"
"He cant help it, hes just an Arm Flapping Fagget. That`s how he was born"
by Smithers john February 1, 2009