Some one who tries to do something and fails miserably, but still thinks they did an amazing job. Usualy if some one is a "tool", they're usualy this as well.
Say your on a sports team with someone. A screw tard would be considered someone who sits the bench the whole game but then hits on chicks and thinks he's cool just because you won the game.
by slangdrummer81 February 07, 2009