When you turn on your windscreen washer and some of the water sprays over the roof of your car and splatters on the windscreen of the vehicle behind, causing them to have to do the same thing. In a line of traffic this can result in a major domino effect.

Extra funny when there is a motorbike or cyclist behind you and they get wet and just have to suck it up and take it.
I was backsplattering in traffic and I totally backsplattered this dude on a bike, it was tooooo funny.
by Flash the Squirrel March 25, 2011
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noun. The remainder of fecal matter on the back of the toilet bowl where it resembles the effects of a spraycan.
John ate too many burritos last night, and you can tell his body didn't like it from the backsplatter evidence.
by WaterMage July 14, 2008
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