unsound

这一结论站不住脚，因为它基于错误的前提。

The conclusion is ___unsound, relying on false premises.

她的理论因为缺乏实验数据支持而被证明是不可靠的。

Her theory was proven ___unsound due to lack of experimental evidence.

这座老房子的地基不稳固，随时可能倒塌。

The foundation of this old house is ___unsound and may collapse at any time.