The word "crosspurpose" refers to two parties that have conflicting goals or purposes. Its antonyms would be words that describe parties that have aligned goals or purposes. Some examples of these antonyms include "cooperation," "collaboration," "synergy," and "harmony." Cooperation is the act of working together toward a shared goal, while collaboration is the act of working with others to create something. Synergy describes the combined effort of a group that produces a better result than any individual could achieve alone. Harmony refers to a situation where everything is in agreement and working together smoothly. All of these words are antonyms to the word "crosspurpose" as they describe situations where individuals and groups are working together towards the same goal.