"Becoming light" can refer to a variety of things, such as the gradual transition from darkness to daylight or a reduction in weight. Synonyms for this phrase might include "dawning," "brightening," or "illuminating." Other possible options could be "clearing up," "breaking dawn," or "daybreak." "Lightening" might also be a good choice, especially if the focus is on shedding excess weight or reducing a burden. Overall, there are many ways to describe the process of "becoming light," and choosing the right synonym will depend on the exact context and intended meaning of the phrase.