The phrase "casting a stone at" means to criticize or condemn someone harshly. There are several synonyms for this phrase, such as "throwing shade," "throwing rocks," "flinging mud," "hurling insults," or "launching attacks." Each of these phrases conveys a negative attitude towards the person being criticized and implies that the criticizer is belittling or trying to cause harm. It's important to remember that words have power and can hurt others, so it's best to choose our language carefully and avoid using phrases that could be hurtful. Instead, we should focus on constructive criticism and encouraging words.