The phrase "cat-and-dog" typically refers to a contentious or hostile relationship between two individuals or things. Antonyms for "cat-and-dog" could include "harmonious," "peaceful," "amicable," "friendly," "congenial," or "agreeable." The opposite of a "cat-and-dog" relationship is one where both parties get along and work together towards common goals. Such partnerships involve mutual respect and trust and can result in positive outcomes for all involved. Using antonyms for "cat-and-dog" can be helpful in describing relationships and situations that are not characterized by conflict, and can help emphasize positive and productive interactions between people or things.