The quality of being impenetrable (by people or light or missiles etc.).

synonym: imperviousness.

Roget 321: density, solidity; solidness etc. adj.; impenetrability, impermeability; incompressibility; imporosity^†; cohesion etc. 46; constipation, consistence, spissitude^†.    specific gravity; hydrometer, areometer^†.    condensation; caseation^†; solidation^†, solidification; consolidation; concretion, coagulation; petrification etc. (hardening) 323; crystallization, precipitation; deposit, precipitate; inspissation^†; gelation, thickening etc. v.. indivisibility, indiscerptibility^†, insolubility, indissolvableness.    solid body, mass, block, knot, lump; concretion, concrete, conglomerate; cake, clot, stone, curd, coagulum; bone, gristle, cartilage; casein, crassamentum^†; legumin^†.    superdense matter, condensed states of matter; dwarf star, neutron star.    ... show more

Polish: niepoznawalność

Incomprehensibility by virtue of being too dense to understand.

synonym: impenetrableness.

Polish: nieprzenikliwość