The phrase "shone up to" basically means to present oneself in the most impressive way possible, to sparkle or shine, either literally or metaphorically. There are several antonyms for this phrase, including "dulled down," "dimmed," "obscured," "masked," and "hidden." These words describe the opposite of the shining, eye-catching effect that "shone up to" creates. While "shone up to" suggests a deliberate and confident display of one's best self, the antonyms suggest a more subdued, modest, or even self-effacing approach. Depending on the context, any of these antonyms could be used to convey a sense of humility, restraint, or simply a lack of interest in impressing others.