it has different meanings in American and British English. Check for example: http://www.oxfordlearnersdictionaries.com/definition/english/tradesman
I think of a tradesman as one who practices a trade; I don't know why we distinguish between trades and professions. A doctor was surprised when he got his plumbing bill. "I don't make that much and I'm a brain surgeon!" "Yeah, I didn't make that much when I was a brain surgeon either."