Impenetrable

Impossible to pass through, enter, or break into; not able to be pierced, entered, or understood. It can refer to physical barriers like solid objects, abstract concepts like secrecy or mystery, or psychological states, highlighting an inability to be affected or moved by something. The word emphasizes the utter inaccessibility of the subject.

Impenetrable meaning with examples

• The ancient fortress was protected by walls of seemingly impenetrable stone, making it virtually impossible for invaders to breach their defenses. Soldiers, archers and the terrain all conspired to create an impregnable barrier for any prospective attacking force. Any assault had to be mounted against the defensive position over some period of time to have any possibility of success.
• The detective found the suspect's alibi impenetrable; every detail seemed to align perfectly, leaving no room for doubt. Despite extensive interrogation and circumstantial evidence, the investigation stalled as the wall of the alibi remained solid and unshaken with no way in, leaving the investigator and his team in a state of frustration.
• During the battle, the thick fog formed an impenetrable screen, obscuring the enemy's movements and making it difficult to distinguish friend from foe, thus complicating the engagement considerably and slowing the conflict. The lack of visibility increased the tension and the chance for friendly fire.
• Despite years of study, the complexities of quantum physics remained largely impenetrable to her, the concepts were too difficult to grasp, the ideas were too complex. Although she knew a lot about the subject, she remained in awe of the scope of the discipline.