A speed demon is someone who loves to drive fast and recklessly. HOTROD, a 6 letter word, is a slang term for a car that has been modified for speed. A BUS, a 3 letter word, is a large vehicle used to transport people. RACER, a 5 letter word, is someone who competes in a race. Leadfoot, an 8 letter word, is another slang term for someone who drives too fast. All of these words can be used to describe a speed demon.