A physical and public humiliation defined by a light tap to the back of the neck originating at Arvin High School. A successful chap is characterized by a faint, but very distinguishable smacking sound, followed by laughter among those present.
It may also be used to describe an object that is sub-par, un-cool, stupid, or of poor quality.
One may precede a chap by saying the following:
"That's a chap"
"That burger was a chap!"
"Don't make me chap you!" (As a warning)