Colorfastness refers to the ability of a fabric or material to resist fading or bleeding during exposure to various conditions like light, water, or chemicals. Synonyms for this word include color stability, color retention, color endurance, and color steadfastness. These terms refer to the same quality of being resistant to color loss or fading. Other alternatives for colorfastness are permanent color, colorfast, color-resistant, and color-protected. These words are commonly used to describe materials that retain their color after washing, exposure to UV rays, or other harsh environmental factors. It's important for fabrics to have good colorfastness to ensure they remain vibrant and attractive over a long period of time.