unassailable

The adjective unassailable means without flaws or indefensible. If you are going to get home late (again!), you'd better have an unassailable alibi for your parents, or else you should plan on not seeing the outside of your room for a while.

The adjective unassailable also means immune to attack or doubt, such as an unassailable military holding or an unassailable reputation. Unassailable can also mean untouchable or unable to be defeated. If your high school basketball team is leading 92 to 14 with just a couple of seconds to go, the announcer might say you have an unassailable lead. The corrupt politician had so many connections, he seemed unassailable; he always seemed to manage to deflect even a hint of scandal onto others in the party.

Definitions of unassailable
1

adj impossible to assail

Synonyms:
untouchable
inviolable
incapable of being transgressed or dishonored

adj immune to attack; incapable of being tampered with

Synonyms:
impregnable, inviolable, secure, strong, unattackable
invulnerable
immune to attack; impregnable

adj without flaws or loopholes

Synonyms:
bulletproof, unshakable, watertight
incontestable, incontestible
incapable of being contested or disputed

Sign up, it's free!

Whether you're a student, an educator, or a lifelong learner, Vocabulary.com can put you on the path to systematic vocabulary improvement.