unimpregnable

adjective2

1. •
   Not impregnable; capable of being pierced or assailed.

   • Without being a coward, Jean's courage is not unimpregnable, and therefore plays he not the swaggerer amongst the patients. — 1840
2. •
   Incapable of being impregnated; impermeable or infertile.

   • The compound rendered the surface of the vessel unimpregnable.
   • Despite fertility treatment, one out of three women in the study remained unimpregnable.