The term "ratchet" has to be the most overused word in hip-hop and Black culture since the endearing word "hater", but who is ratchet?

What makes them ratchet? Here is the Urban Dictionary definition of ratchet. I don't agree with it because I have heard of men, places and things being referred to as being ratchet. So I think we can come up with a better definition than this.

Let me know -- what's your definition of "ratchet"??