When you say someone is on the wrong side of something, it means they have taken a position that is not well-received or supported by others. Some synonyms for this phrase include "opposed to," "disagreeing with," "at odds with," or "out of sync with." Other options are "against," "contrary to," or "in defiance of." All of these phrases convey the same message: that the person in question is taking a stance that is outside of the accepted norm, or that is causing problems for those around them. Whether it's a political issue or a matter of personal opinion, being on the wrong side of something can be a lonely and difficult place to be.