Which word would best describe an unruly mix or confusion in activity?

The term that best describes an unruly mix or confusion in activity is "welter." This word conveys a sense of chaotic jumbling or a disordered state, often involving various elements that are tangled or in a state of uproar, which aligns perfectly with the idea of confusion or disorder in activity. The root connotation of "welter" suggests a turbulent or chaotic situation, making it fitting for describing an unruly mix.

In contrast, "quiescence" denotes a state of inactivity or calmness, which is the opposite of confusion or disruption. "Virago" refers to a spirited or determined woman, typically with connotations of assertiveness rather than chaos. Lastly, "propitiate" means to placate or appease someone, which does not relate to the mixing or disorderly activity described in the question. Thus, "welter" stands out clearly as the word that encapsulates the intended meaning of confusion and turmoil.