POSH: smart, elegant, and fashionable; upper class.
Posh is not so much a subculture. You just are Posh or you're not. You can be born Posh (born high class), but you can also become Posh. Posh speak with the highest grade accent, are very classy, sophisticated, and own high-quality things. We here at Hella Cliques believe that one can be Posh on a budget. However, in England, where they use the term the most, Posh does mean upper class and upper class connotates wealthy.