"Was one side" can be replaced by different synonyms depending on the context. If it refers to a conflict or argument, "was one side" can be substituted with "took a stand," "chose a position," or "aligned with a particular viewpoint." In a physical setting, "was one side" can be replaced with "occupied" or "standing on," while in a comparative context, synonyms such as "one of" or "one among" can be used. Overall, the replacement of "was one side" with alternative phrasing adds diversity and clarity to writing or conversation.