1. removing color from something; making something colorless or less colored
Usage: present participle of decolorize; chiefly British spelling (American: decolorizing)

Examples

• The sun was decolourizing the old fabric over time.
• Chlorine is effective at decolourizing stains in laundry.
• The chemical process involves decolourizing the raw material before refinement.
• Prolonged exposure to light was decolourizing the painting.
• The treatment is decolourizing the water by removing impurities.