This word popped up when the MP Andrew Mitchell yelled at the police guarding Number 10 because they wouldn't open the main gate to let him through but instead made him use the pedestrian gate.

Pleb means commoner. It is used to differentiate that the person speaking is above the person he is addressing.

The MP later resigned after many weeks of controversy. It was found later that he did not use this word.

All the Best!

American to Britain