The term "co-active" is used to describe a state of working together in collaboration or partnership. Antonyms for this word could include words like "competitive," "isolated," "divisive," or "disruptive." These words suggest a state of being apart or working independently, often in opposition to others. They may also indicate a lack of cooperation or communication between individuals or groups. Other antonyms for "co-active" might include words like "passive," "uninvolved," or "detached," which suggest an unwillingness or inability to engage in joint efforts. Overall, these antonyms highlight the importance of collaboration and cooperation in achieving shared goals.