Ok, in working on Hyb Ciuin, I am doing descriptions of the City Guard the City Watch.
The Guard are essentially the city police force. They were copper colored cloaks (it is how they are identified - ranks within the Guard are denoted by badges on the leather armor that they wear). This means that they are often called Coppers after the cloak that they wear, or sometimes that is shortened to just "Cops" (anecdotal/maybe-historical note: police got the nickname of coppers (also shortened to Cops) from thier copper badges that they would wear).
Now, the Watch, stands guard on the walls of the city. They wear mottled grey cloaks (think quasi-camoflage pattern), meant to match or blend into the stone of the city walls (making them harder to spot for those trying to nseak into the city). This has led to them being often referred to as Stones, or more commonly called Rocks.
Unfortunately, The Watch does not have the best reputation. Being considered not overly bright, and also a bit rougher and/or meaner than they have to be. This has led to the adoption of some common phrases. For example, being in trouble is sometimes referred to be "between a Rock and a hard place" and if a person is not very bright they could be referred to as being "as dumb as a Rock".
Thoughts? Comments?