The antonyms for the phrase "become colorless" are many and varied, as there are numerous ways to describe the opposite of losing brightness or vibrancy. Some possible antonyms might include the terms "brighten," "vivid," "colorful," "radiant," "incandescent," or "lustrous." Other options might include words like "vibrant" or "saturation," which offer a more nuanced and specific way to describe the opposite of becoming colorless. Regardless of which antonym one chooses to use, it's clear that the word "colorless" has many diametrically opposed options when it comes to describing an object or phenomenon that is saturated with color and life.