When we use the phrase "break out," we usually mean some kind of sudden or unexpected event or occurrence. However, there are plenty of synonyms that can be used in its place depending on the context. Some options include "erupt," "burst forth," "spring up," "start," "ignite," "develop," "begin," "commence," "happen," "occur," and "unfold." Depending on the situation, using a variation of "break out" can help to add emphasis or clarity to what's happening, or convey a slightly different meaning. So, whether you're discussing a new business venture or a sudden illness, there are plenty of ways to express the idea of something breaking out!