Someone who has trouble with things in general. Poor comprehension or bad coordination makes this person incapable of performing well.
At the end of a losing match, the captain said: "what happened today? we looked like a bunch of mulaks out there!"
Two friends are trying to figure out what transportation to take:
Tim: "why don't we take our bikes, this way we can go around the traffic"
Jeff: "I know... why don't we take our bicycles so that we don't have to get stuck in traffic"
Tim: "That's what I just said, you mulak"