Not to be stormed, or taken by assault; incapable of being subdued; able to resist attack; unconquerable; as, an impregnable fortress; impregnable virtue.
Capable of being impregnated, as the egg of an animal, or the ovule of a plant.
Incapable of being fatigued; not readily exhausted; unremitting in labor or effort; untiring; unwearying; not yielding to fatigue; as, indefatigable exertions, perseverance, application.
Immovably.
To loose from shackles or bonds; to set free from restraint; to unfetter.