What are the opposite words for secondarily?

The antonyms for the word "secondarily" include primarily, firstly, initially, chiefly, and fundamentally. These words describe actions or thoughts that have the highest priority or are the most important. When something is done primarily, it means that it is the main focus, the first thing to be done, or the most important task. Firstly is similar, referring to the first step or initial action in a sequence of events. Fundamentally suggests that something is at the core or foundation of an issue. Each of these words opposes secondarily and emphasizes the critical nature of that which is being described.