Lost luster is a term used to describe something that has lost its shine, sparkle, or vibrancy. The two crossword solutions for this term are FADED and PALED, both of which refer to the gradual loss of color or brightness. FADED implies a gradual decrease in intensity, while PALED suggests a more sudden change in hue. Both words can be used to describe the dulling of something that was once vibrant and full of life.