The phrase "parts company" usually signifies two entities or individuals going separate ways or ending their association. The antonyms for this phrase are words or expressions that suggest staying together, continuing a relationship, or agreeing. Some of the antonyms for "parts company" include join forces, collaborate, merge, unite, bond, stay, remain, and reconcile. For instance, instead of choosing to "part company," parties could decide to "merge" or "join forces" for a common goal. Alternatively, they could choose to "bond" or "unite" and maintain a healthy relationship. Therefore, using antonyms for "parts company" could pave the way for new opportunities, collaboration, and growth.