There are several different synonyms that can be used for the phrase "go down in someone's opinion." One might say that someone "lost favor" or "fell from grace," suggesting that they were once respected but have now been viewed less favorably. Alternatively, one could say that someone has "lost respect," "lowered themselves," or "disappointed." Words like "tarnished" or "stained" might also be used to suggest that someone's reputation or image has been damaged. Whatever the specific wording used, the overall implication is that someone's behavior or actions have led to a loss of respect, admiration, or trust among those around them.
