I do object to their claim, which I find totally unsubstantiated.
我确实反对他们的说法，我发现那是完全没有根据的。
《柯林斯英汉双解大词典》
2
There are reports that some military aircraft flew information when they were low on fuel during the Second World War, but Dr. Lissaman says they are unsubstantiated.
有报道称，二战期间，一些军机曾在燃料不足的情况下编队飞行。但利萨曼博士表示，这些说法没有根据。
3
Most negative comments, on both sides, are usually technically unsubstantiated.