Co-here means to stick together in a cohesive manner. Therefore, antonyms or words that mean the opposite of "co-here" are words that imply a lack of unity or solidarity. Some antonyms for "co-here" include disperse, scatter, separate, segregate, and divide. When a group is dispersed, they are spread out and not together. When something scatters, it moves in different directions, indicating a lack of cohesion. To separate is to move apart or to distinguish between entities. Segregate means to isolate or set apart from others, while divide means to separate into different parts. All these antonyms suggest a lack of togetherness or unity.