The word "achromatize" refers to the process of removing color or making something colorless. Its antonyms, on the other hand, are words that convey the opposite meaning. The first antonym of "achromatize" is "colorize," which means to add or intensify color to something. Another antonym is "hue," which is a term used to describe any color of the spectrum. "Pigment" is another antonym that refers to any substance used to dye, paint or color something. Lastly, "chromatic" can be used as an antonym of "achromatize," meaning anything that has color, especially bright or vivid colors. These antonyms serve as a helpful tool in communication and understanding the nuances of language.