"Square off" is a common idiomatic expression which means to prepare for a fight, argument, or competition. If you're looking to add some variation to your expression, there are several synonyms that can be used instead. One alternative is "settle a score," which is another way of saying to resolve a conflict or dispute. Another synonym for "square off" is "face off," which is typically used in sports to describe two opposing teams beginning a game. Additionally, "lock horns" can be used to describe two people or groups who are engaged in an intense confrontation or disagreement. Lastly, "clash" can be used to describe a strong disagreement or conflict between people or ideas.