If you are fuddled, your mind is not clear. Drink is the usual cause, and then it means a bit drunk — not falling-down drunk, but mixed-up and slow. Heat, tiredness, or a strong medicine can leave you fuddled too. It is the -ed form of fuddle, used like an adjective: you are in that state. It sounds a little old and a little British, the kind of word a novel might use: “He woke up fuddled.” Though actually, in everyday talk a younger speaker is more likely to say confused, groggy, or “I can’t think.” It is not rude, and it is not a joke about old-fashioned people — that is a different word, fuddy-duddy.