A person who is exceptionally adept at being clueless about what is happening around them. More often than not, a lemeard will respond in such a way that no one around him or her understands what the lemeard is trying to say. Because they have such a hard time interacting at social gatherings, they are often misconstrued as being very boring, although fun to laugh at, people and are called lameards to accentuate their overall lameness.
What the fuck is that lemeard janitor trying to say to those kids? "Hey you, lameard, shut the fuck up because nobody cares!"