Circuitous means indirect or roundabout. If you're already late for school, you'll want to take the straightest, fastest way there, not a circuitous one!
Circuitous comes from the Latin word circuitus meaning "a going around." If you're being circuitous it's like you're going around and around in circles. It can also refer to someone's manner or speech, if they are not being direct. For example, if you want someone to get you another piece of cake, but just you sit there looking longingly at your empty plate and talking about how delicious cake is, then you're being circuitous. And annoying.