To "talk trash" is to make negative comments or insults about someone or something. There are many synonyms for this phrase, such as "badmouth," "dish the dirt," "slam," "trash-talk," "vilify," and "slander." Other similar phrases include "throw shade," "cast aspersions," "spread rumors," and "smear." These words and phrases can be used in various contexts, from personal conflicts to political debates. It is important to avoid talking trash because it can hurt others' feelings and damage relationships. Instead, try to speak kindly and respectfully to others, even in times of disagreement.