Dead good. Yes. I love the British slang use of the word "dead" when it is used to emphasize things. It's dead brilliant! (very brilliant) You can say that your "mate" (your friend or co-worker) is "dead stupid", for example. This means he's "thick as a brick", to put it another way. It really conveys the idea powerfully. You can't BE more stupid than "dead stupid". I imagine you could even say that someone is "dead lively" to mean not that he is one of the living dead, but that he has an unusual amount of vitality. Vim and vigor, as it were.    I hope so, anyway. It's a dead useful expression, if you ask me.