哗然 (huá rán) is an adjective describing a public uproar or outcry, often used in formal/written contexts (e.g., 舆论哗然 'public opinion in an uproar'). Unlike the verb 轰动 (hōng dòng 'to cause a sensation'), 哗然 describes the resulting state of clamor, not the act of creating it. It also differs from 喧哗 (xuān huá 'noisy'), which refers to general noise rather than a collective protest or controversy.