unassailable.

1. So well supported or secure that it cannot be successfully challenged on the relevant grounds.

2. So protected that it cannot readily be taken or overcome by an attack.

Use it for

Words that belong together

• unassailable argument
• unassailable position

On the page

The evidence made the narrow conclusion unassailable without supporting the broader accusation.

His authority seemed unassailable until the archive revealed how it had been constructed.

Usage notes

Primary category: literary / elevated general. Forms: Comparative more unassailable; superlative most unassailable where gradation is meaningful. Legacy lexical fields mirror sense 1 only. Use numbered sense fields for all meanings. Established modern English lexical item. No separate regional spelling or grammatical inflection entry. Writing functions: description, interpretation, contrast, characterization. Disciplines: prose writing, literary analysis, advanced general English. Commonness: moderately common.