Did you maybe mean unattainable?
- From un- + attack + -able (Wiktionary)
“I will make covered chariots, safe and unattackable, which, entering among the enemy with their artillery, there is no body of men so great but they would break them.”
“A superior who reproves such gossip holds an unattackable position.”
“And were this to be so, and the being I loved best of all in the world came and asked me which he should choose -- which refuge I held to be most unattackable, sweetest, profoundest -- I would surely advise him to shelter his destiny in the refuge of the soul that grows nobler.”
“A woman without vanity would be unattackable," resumed the Man of”
“Lupin, ex-burglar, ex-convict, ex-anything you please -- I'm unattackable on that ground -- but as Don Luis Perenna, respectable man, residuary legatee, and the rest of it.”
“It is as unattackable in consequence as in the past were our religious ideas.”
“We accept this definition as true and unattackable, although nothing could be more false.”
“The resisting power of numbers, the unattackable stolidity of a great multitude, was the haunting fear of his sinister loneliness.”
“As the temple terrace thus became the principal defence of the city on the east side, there were no gates or openings in that direction, and being situated on a sort of rocky brow -- as evidenced from its appearance in the vaults that bounded it on this side -- if was at all later times considered unattackable from the eastward.”
“Yet these instinctive postponements of reflection were the fruit, positively, of recognitions and perceptions already active; of the sense, above all, that she had made, at a particular hour, made by the mere touch of her hand, a difference in the situation so long present to her as practically unattackable.”
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