1. verb, slang To smile with the eyes. Popularized by model Tyra Banks on the TV show America's Next Top Model as an instruction for the models to not smile with their mouths but instead convey a smiling expression with their eyes. Her pictures always look gorgeous—she's great at smizing for the camera.
2. noun, slang A facial expression in which one (typically a model) does not smile with the mouth but instead conveys a smiling expression with their eyes. Her pictures always look gorgeous—she's gives a great smize.