A gadget that is user-friendly is easy to use. User-friendly devices can be used quickly, even if you haven't used anything like it before.
Have you ever tried to use something like a video camera and had a hard time figuring out how to use it, even after reading the instructions? Devices that are difficult to use are not user-friendly. A user-friendly device is easy to figure out. The designer has thought about how a new user would approach it and has made the experience simple. Just about anyone can pick a user-friendly device up and start using it.