To enter into; to make way into the interior of; to pierce.

“Light penetrates darkness.”

To achieve understanding of, despite some obstacle; to comprehend; to understand.

“I could not penetrate Burke's opaque rhetoric.”

To affect profoundly through the senses or feelings; to move deeply.

“to penetrate one's heart with pity”

Able to pierce or penetrate

“The skunk produces a penetrating odor.”

Demonstrating acute or keen understanding

“His novel shows a penetrating insight into the criminal mind.”