1. A person or animal that drinks liquid by lapping it up with their tongue. The vampire bat, that famous winged lapper of blood, is actually far less dangerous than popular mythology leads us to believe. Struggling for adequately insulting words, she called him a piss-lapper and stormed off.

2. A race that is won by completing a certain number of laps before the other competitors. The amount of laps is specified right before "lapper" with a number and a hyphen. It was the first time the race car driver won the 100-lapper in his entire career.

3. A person that one is about to overtake in a race consisting of multiple laps. The runner is about to speed past yet another hapless lapper.