- authenticity UK US /ˌɔːθenˈtɪsəti/ noun [U]► the quality of being real or true: »
Many people now question the authenticity of his claims.ensure/guarantee sth's authenticity »
Digital signatures ensure the authenticity of your documents.check/verify sth's authenticity »
They showed the documents to several experts to verify their authenticity.
Financial and business terms. 2012.