Unassailable
ahd-5
adjective.
Impossible to dispute or disprove; undeniable.
adjective.
Not subject to attack or seizure; impregnable.
The Century Dictionary and Cyclopedia
Not assailable; incapable of being assailed; incontestable; hence, not to be moved or shaken from a purpose.
Wiktionary, Creative Commons Attribution/Share-Alike License
adjective.
secure
against
attack
;
impregnable
adjective.
undeniable
,
incontestable
or
incontrovertible
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adjective.
impossible to assail
adjective.
without flaws or loopholes
adjective.
immune to attack; incapable of being tampered with
Word Usage
"Her use of the expression unassailable patriarchy arguably may not include all male Catholics."