Achromatization refers to the process of removing color or rendering something colorless. This word can be replaced with other synonyms that convey the same meaning. For instance, the word "bleaching" might be used to describe the process of removing color from paper or fabric. Another word that could be used in place of achromatization is "decolorization", which refers to the process of making something colorless. Similarly, the word "whitening" could be used to describe the process of making something white, which often involves removing color. In general, synonyms for achromatization tend to describe the process of removing or reducing color from an object or substance.