The phrase "enemy line" is most often used in reference to military conflicts and battlefields. However, there are several other phrases and words that can be used to convey a similar meaning. One of the most common is "frontline," which refers to the area where opposing armies engage in combat. Other synonyms include "battle zone," "warzone," and "no man's land." In a political or social context, terms like "opposition," "rival," and "adversary" can be used to describe individuals or groups with opposing viewpoints or goals. Whatever the context, these synonyms all convey a sense of conflict or opposition between groups.