Antonyms for the phrase "cast aspersion" include phrases such as praise or compliment. While casting aspersions involves making negative or critical comments about someone or something, praising or complimenting involves highlighting the positive qualities or actions of someone or something. Other antonyms for casting aspersions include admire, approve, applaud, and commend. These words convey positivity, which is opposite to the negative connotation of casting aspersions. Using antonyms like these can help to create a tone of positivity and appreciation instead of negativity and criticism.