Synonyms of untenable

2 Syllables
unsound, flawed
3 Syllables
baseless
4 Syllables
inexpiable, illogical, incredible, foundationless
5 Syllables
unforgivable, inexcusable, indefensible, criticizable, unpermissible, unsustainable, unwarrantable, unsupportable
6 Syllables
counterintuitive, uncorroborated