"Was cahoots" typically describes a situation where two or more people conspire or collaborate with each other for illicit reasons. Antonyms for this term could include terms like "alone," "separated," or "individual." These words would emphasize a sense of independence or isolation rather than collaboration. Other antonyms could include "opposed," "conflicting," or "antagonistic," which would suggest a sense of hostility or disagreement rather than cooperation. Essentially, any words that contrast the sense of collaboration implied by "was cahoots" could serve as antonyms for this term, depending on the context in which it is used.