The phrase "is cahoots with" refers to a close collaboration or partnership between two or more individuals or groups that are often engaged in something illegal or unethical. Besides "is cahoots with," there are several synonyms that can be used to convey the same meaning. Some of the synonyms for this phrase include "in league with," "in cahoots with," "in partnership with," "in collusion with," "hand in glove with," "associating with," and "connected with," among others. Each of these synonyms carries a slightly different connotation, but they all imply a sense of secrecy and cooperation between parties involved in questionable activities.