Also can be used to describe a person who sucks at sports, work or basically anything related to daily life.
You: "Man that kid is such a yard stick, what a stupid question"
Friend: "OMG such a retard haha"
Random person: Slips and falls on ice or trips on random thing
You: "Man did you see that yard stick wipe out?!?!"
Friend: "Ya he totally just ate it hahaha!"