This question specifically covers how these terms are used to describe language, it is a followup to What's the difference between "informal", "colloquial", "slang", and "vulgar"?
In the former question it arose that vulgar has at least two senses, and perhaps three:
- "of the people" as in Vulgar Latin (not considered to be a productive sense anymore)
- an antonym to "refined" as used to label words in various dictionaries
- a synonym for "obscene" or "offensive" - I take this sense to be newer and perhaps regional to America - but it does seem to be replacing sense 2
So my question is how do these other words overlap in meaning with the 2nd and 3rd senses above: "coarse", "crass", "crude", "rough", "rude", "unrefined"?