Pothouse was a word coined, I think, by Ginger Barwick - Bravado merchandiser and wide-boy to the stars. I can only assume it comes from a mixture of crackpot and madhouse and is used to describe those of a slightly unstable nature.
* These videos are coming directly from Youtube, they may or may not be most relevant to the word "Pothouse"
What is Define Dictionary Meaning?
Best thing is, its free and you can even contribute without creating an account.