This argument is untenable from an intellectual, moral and practical standpoint.

从知识、道德和现实的角度来看，这种论点是站不住脚的。

《柯林斯英汉双解大词典》

That argument is untenable. /The argument does not hold water.

这个论点不能成立。

youdao

I believe that the above argument is untenable.

我认为，以上论点是站不住脚的。

youdao

Mr Justice Ouseley ruled "untenable" the argument that the inspection policy had been changed to evade the effective inspection of animals in transit.

BBC: RSPCA fails to halt live sheep exports from Ramsgate