Devious means to be clever in planning things to go a certain way to get results that are wanted, often through methods that people don't expect, either because they are unusual methods or because they are not quite playing normal rules. It doesn't have to involve malice in any way, and the word can suggest a kind of admiration mixed in with it. The basic meaning is a kind of shadowy or sneaky cleverness.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.