"Diss" is a slang term that is short for "disrespect" or "disparagement." In this context, it refers to an insult or a disrespectful comment directed towards someone. It is often used in informal or colloquial speech, particularly in the context of casual conversations or music lyrics.
Note: The provided meaning of the answer is for the latest New York Times crossword puzzle clue: Hate on, informally. Explanations are generated by AI and may be inaccurate.