impregnable
adjective
[ ɪmˈprɛɡnəb(ə)l ]
• (of a fortified position) unable to be captured or broken into.
• "a massive and impregnable fortress"
Similar:
invulnerable,
impenetrable,
unattackable,
unassailable,
inviolable,
secure,
strong,
stout,
safe,
fortress-like,
well fortified,
well defended,
invincible,
unconquerable,
unbeatable,
indestructible,
Origin:
late Middle English: from Old French imprenable, from in- ‘not’ + prendre ‘take’ (from Latin prehendere ). The current spelling arose in the 16th century, perhaps influenced by Old French variants.
