Antonyms for the phrase "be in cahoots with" include cooperation, collaboration, teamwork, alliance, partnership, and camaraderie. These words imply a positive and advantageous working relationship between parties. The opposite of being in cahoots with someone is to be an adversary, foe, or opponent. These antonyms suggest a competition or lack of trust between parties. Being independent, uninvolved, or neutral is also an antonym for being in cahoots with someone. Choosing to work alone or not participate in schemes, deals, or plans with others can be a beneficial approach in some situations.