The term 'lightens in color' can be summarized by the crossword solution 'pales, ' which is a five-letter word. To 'PALE' means to become lighter in color, usually referring to a gradual lightening of a hue. This term is often used to describe skin tone, as when someone blushes or becomes embarrassed, their skin may PALE. It can also be used to describe other objects, such as fabric or paint, that become lighter in color over time.