unassailable
adj. 不容置疑的；无懈可击的
例句
Our seemingly unassailable lead in speciality manufacturing has dwindled.
我们在特殊产品制造上似乎不容置疑的领先优势缩小了。
《柯林斯英汉双解大词典》
Its concepts are woolly and untestable, yet are regarded as unassailable axioms.
它的概念模糊而不可测试，但却被认为是公理而无懈可击。
The party now has an unassailable lead.
这个党的领先地位现在坚不可摧。
《牛津词典》
