Reflective is an adjective that can describe a person who thinks things through, or a surface that reflects light or sound, like the reflective lettering on a stop sign.
To reflect is to bounce back an image, light, or sound. A reflective surface is one that can bounce back light — like the reflective sun shade that you put over the windshield of your car. It bounces the sun's rays away, helping the interior cool. A reflective person is a little different — he or she might have great insight due to taking the time to time carefully about things.