If a principal steps into a classroom and is greeted by a tumult of voices, with the teacher shouting for his kids' attention, she will not be pleased. A tumult is a state of noisy confusion.
Very often a crowd of people will cause a tumult. But your mind can also be in tumult, when you're confused and overwhelmed by strong emotions. If you want an adjective to describe these types of bewildering situations, use tumultuous. Tumult is from the Latin tumultus "an uproar," which is related to the Latin verb tumēre "to be excited."