The act of pretending to "set up" for a high five, only to scream "Betrayal Five" and then to slap the chest area of a friend. This is normally done to throw the friend off-balance or to steal something that they have. This term was coined by Todd in the TV show Scrubs.
Steve: Dude, I just found a $20 bill laying on the ground!
John: Sweet! ...Betrayal five!
*John slaps Steve, Steve drops the $20 bill, John picks it up and walks away.*
It starts out like a high five
, you raise your hand and when the other person raises their hand, start to do a normal high five but right before your hands touch, bring down your hand, rotate your hand 90° to the right and tilt it forward so it should just be your hand is horizontal with the palm facing down, dodge their high five, and karate chop them in either the chest or stomach. For added effect, say "High Five!" before and then say "Betrayal Five!" after you hit them.
Shawn: High-five, dude!
^Instead of a high five, Shawn slaps Albert in the chest area^