Definition of "unsubstantiated"

Such hedging is necessitated by the lack of in-depth knowledge of the contents, which also gives free rein to the scripting of unsubstantiated factoids concerning the book.

2018, James Lambert, “Setting the Record Straight: An In-depth Examination of Hobson-Jobson”, in International Journal of Lexicography, volume 31, number 4, page 487