Antonyms for the phrase "am in cahoots with" would include "oppose," "oppose vigorously," or "be at loggerheads with." These words suggest a sense of disagreement or conflict, rather than a cooperative or conspiratorial relationship. Other antonyms might include "disassociate," "disavow," or "disown," indicating a complete lack of connection or affiliation. Alternatively, "ignore," "neglect," or "overlook" suggest a lack of interest or attention to the person or situation involved. Overall, these antonyms emphasize the importance of independence, integrity, and honesty in human relationships, rather than collaboration or collusion.