From the
root word "
Yokel". It is generaly used as a derogatory term for a bad driver,
however it can also be used to describe someone as inferior mentally. It implies a certain level of redneck culture and inbreeding in the driver or person it is being yelled at.
When you come around a corner to find someone stopped in the middle of the highway, "What is this Yoker doing?"
When someone tries to pass you when you stop for a flagger in a construction zone and
almost runs head
first into oncoming traffic, "You freakin Yoker!"
When someone tries to impress people by doing
something he has very littke skill or experience in, "What a yoker!"