There are many synonyms for the phrase "became dim," which is generally used to convey a loss of brightness or clarity. Some alternatives include "faded," "diminished," "obscured," "dulled," "veiled," "clouded," "shadowed," "weakened," and "waned." Each of these words offers a slightly different nuance, suggesting different degrees or types of shading or obscuring. For example, "faded" implies a gradual loss of brightness, while "obscured" suggests an obstruction or hiding of the source of light. Wisely choosing a synonym for "became dim" can help writers to create vivid and precise imagery in their descriptions.