untenable.

Unable to be defended or sustained under the circumstances.

Use it for

Words that belong together

• untenable position
• untenable assumption

On the page

The new evidence made the earlier assumption untenable.

Usage notes

Primary category: analysis / argumentation / evidence. Forms: Comparative more untenable; superlative most untenable when comparison 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: evidence, inference, qualification. Commonness: moderately common.