The antonym for the word "loses luster" would be "gains shine" or "becomes shimmery". When an item or thing loses its luster, it becomes dull, lackluster or has lost its shine. However, the opposite can be said when something gains shine, it becomes brighter, more glittering, and more appealing to the eye. There are various ways to bring back the shine of something that has lost its luster, such as polishing, cleaning, or restoring it. It is always advisable to take care of our belongings, so they don't lose their luster and stay shiny and looking new for longer periods.