By the way, you needn't worry any of these words being bad or dirty. Number 3 has a vulgar meaning (which you can find in a dictionary, as Jonathan recommends), but when British people say it in everyday situations we don't mean it in that sense. It's just a way of showing annoyance and surprise. I'm a fairly polite person, but I say 'bugger'. It's more funny than offensive, and has nothing to do with the meaning you'd find in the dictionary.
Even number 5, when used between male friends, isn't particularly vulgar.