"In uproar" is an idiomatic expression that refers to a state of commotion, chaos, and disorder. There are several synonyms that can be used in place of this phrase, such as tumult, pandemonium, uproariousness, turmoil, bedlam, mayhem, and commotion. These words can be used interchangeably based on the context in which they are used. For example, we can say, "the stadium was in an uproar after the home team scored a last-minute goal," or "there was bedlam in the streets after the carnival procession passed through." Each synonym offers a unique nuance to the overall meaning of the sentence, but all convey a sense of chaos and disturbance.