unsubstantiated
adj. C1 Advanced US //ˌənsəbˈstænʃiˌeɪtɪd// UK //ʌnsəbstˈænʃɪˌeɪtɪd// un·sub·stan·ti·at·ed
adj. describing a claim or story that has no proof or evidence to support it. You use this when someone says something, but you cannot show that it is true.
adj. lacking evidence or proof to support a claim. Often used to describe allegations or rumors that remain unverified by facts or data.
The police ignored the unsubstantiated rumors about the suspect.
The board of directors dismissed the unsubstantiated claims of financial fraud after a full audit found no evidence of wrongdoing.
While the whistleblower's initial allegations were unsubstantiated, the subsequent investigation revealed a systemic failure in the company's internal compliance protocols.