Not OP, but I'd be happy to try and differentiate, as well. Simple means uncomplicated, not a lot of pieces. A violin is arguably simpler than a guitar because

Not OP, but I'd be happy to try and differentiate, as well. Simple means uncomplicated, not a lot of pieces. A violin is arguably simpler than a guitar because of a lack of frets. Easy means it is not difficult. A guitar is arguably easier than violin [0] because it has frets. It's important to remember that "easy" is very subjective. What is easy for one person might be insurmountable to another. tl;dr "simple" usually means "easy to understand" and "easy" usually means "easy to do". Both inherently assume some amount of prior knowledge or skill, so neither is entirely universal or objective. [0]: I'm not trying to say one instrument is better or disparage and guitarists. It's an example.