look up any word, like kappa:
 
1.
What happens to you when you start nodding off and then you jerk your head back suddenly. Happens a lot when staying on the computer too long. Very dangerous if driving.
If you didn't get enough sleep, and you're driving, please pull over at the first instance of naplash. If possible, get coffee or walk around, or take a proper nap.

I was trying to play SWG the other night, but one of the people in our group kept disconnectin, and I started sufferin naplash.
by Leif April 07, 2005
 
2.
The act of going to sleep for a very brief period of time then waking up suddenly, whipping your head to the upright position.
"I was having a lecture on the political system of Nicaragua, within seconds I was getting naplash"
by ajt May 18, 2005
 
3.
The repercussions from the era during which you downloaded, carefree, gigabyte upon heaping gigabyte of free music from Napster.
1: Dude, I just got an email saying that Roy Orbison's wife is suing me for downloading "Pretty Woman" in 1999.
2: Bummer, that's bad naplash.
by William Segal May 18, 2005