This would be quite useful. English has a free one online at urbandictionary.com, and I've seen Spanish slang guides in bookstores. It would be great if we could start one up, make it a wiki user-editable one so that it can grow quickly. But I think often HKers confuse what "slang" means. In English, slang refers to informal, colloquial, nonstandard words you use with your friends, family, or in t