The term 'opposing group' can be summarized as a group of people or entities that are in opposition to one another. The crossword solution for this term is 'ANTIS, ' which is short for 'ANTAGONISTS.' ANTAGONISTS are individuals or groups that oppose each other, often in a conflict or competition. They may have different goals, beliefs, or values, and they may use various tactics to achieve their objectives. ANTAGONISTS can be found in many different contexts, from politics to sports to literature.