The crossword solution for the term 'become harder to see' is 'FADE'. Fading is a gradual decrease in the visibility of an object or image. It is often used to describe the gradual disappearance of a color or light, such as when the sun sets or when a painting loses its vibrancy over time. Fading can also be used to describe the gradual loss of clarity or sharpness of an image, such as when a photograph becomes less clear with age.