The antonyms for the word "co-adjutant" can vary depending on the context it's used in. If it refers to a military rank, its antonyms can be civilian, pacifist, or enemy. In the context of a job or project, antonyms could be solo, independent, or self-reliant. If it refers to a partnership or collaboration, the antonyms could be adversary, opponent, or solitary. In general terms, opposite words for co-adjutant could include antagonist, adversary, enemy, opponent, or rival. It's essential to understand the context before determining the antonyms for the word "co-adjutant.