l0s3r Posted in L Best definition l0s3r Someone really pathetic. They want to be l33t but even l33t losers consider them to be a loser. The most pathetic form of life. Get out l0s3r before we h4x0r your c0mp00ter. How satisfied are you with the definition? Looking for l0s3r meaning? Delighted that you discovered the greatest determine on our web site! Recently this definition was actually observed 89 times.