What is to a degree resembling death; to the last degree; completely; wholly. [Colloq.] I was tired of reading, and dead sleepy. Dickens. Dead drunk, so drunk as to be unconscious called?

dead — To a degree resembling death; to the last degree; completely; wholly. [Colloq.] I was tired of reading, and dead sleepy. Dickens. Dead drunk, so drunk as to be unconscious. (Webster's 1913.)