Similar to a "faux-five."
When giving some one a high five you stop at the last minute. However, instead of just dodging the high five you form your fiving hand into a finger and shake it at the person. A stern glare should accompany this gesture. Sometimes a loud "No!" is also appropriate.
No-fives should usually be used as friend punishment. A great way to get some ones hopes up then crush them at the last minute.
When Keith told me he finally caught Raiku he thought he was pretty cool... until I No-fived him.
I really deserved the No-five I got after losing to a girl in air hockey.