There are various antonyms for the word "decolor", which means to remove or lose color. Some of the opposite words or antonyms for "decolor" include colorize, tint, pigment, brighten, paint, dye, and shade. The word "colorize" means to add color to something or to bring back its original color. The word "tint" means to add a subtle color to something or to make it slightly colored. Similarly, the word "pigment" means to add color or a substance to color, whereas "shading" means to add or create different shades of colors. In contrast, the word "decolor" refers to the loss or removal of color, which has a negative connotation.