Crossed swords with is a phrase that means to engage in a conflict or argument with someone. Some antonyms for this phrase include cooperating, collaborating, agreeing, harmonizing, and compromising. When people cooperate, they work together to find a solution or achieve a common goal, rather than arguing and creating conflict. Collaboration is similar, but it involves working closely with someone else on a project or task. When people agree, they share the same opinion or belief, which avoids any disagreement. When people harmonize, they are in sync and have a positive, peaceful relationship. Lastly, when people compromise, they give in a little to reach a peaceful agreement.