What does 'rivalry' imply?

The term 'rivalry' fundamentally implies an ongoing competition between two or more parties, often characterized by a desire to outdo one another. This competition can occur in various contexts, such as sports, business, academics, or personal relationships. Rivalry suggests a dynamic interaction where each party seeks to gain an advantage over the other, which can lead to heightened tensions and a drive for improvement.

In contrast, the other choices do not align with the definition of 'rivalry.' A collaborative relationship signifies cooperation and working together towards a common goal, while a casual acquaintance suggests a relationship that lacks depth and competitive tension. An indifferent attitude indicates a lack of interest or engagement, which is contrary to the active and often emotionally charged nature of rivalry.