D defs.my
Entry 2 senses · 2 variants Webster, 1913

Impregnable

/ĭmˌ-prĕg'-nəb-əl/ · Im·preg·na·ble · IPA /ɪmˈpɹɛɡ.nəˌb(ə)l/
01 a. Not to be stormed, or taken by assault; incapable of being subdued; able to resist attack; unconquerable; as, an impregnable fortress; impr…
  1. 1.
    Not to be stormed, or taken by assault; incapable of being subdued; able to resist attack; unconquerable; as, an impregnable fortress; impregnable virtue.
    “The man's affection remains wholly unconcerned and impregnable.” South.
02 a. Capable of being impregnated, as the egg of an animal, or the ovule of a plant.
  1. 1.
    Capable of being impregnated, as the egg of an animal, or the ovule of a plant.(Biol.)