Impervious (adjective)

1. Not allowing something to pass through, especially water or air; impermeable.
2. Not capable of being affected or influenced; insensitive.

Origin:

The term 'impervious' originated in the late 16th century and is derived from the latin word 'impervius' meaning 'impossible to penetrate' or 'impenetrable'.

Examples:

1. The new roof was made of an impervious material that kept out the rain.
2. The castle's walls were nearly impervious to attack, standing strong against even the most powerful siege engines.
3. Despite her best efforts, she could not penetrate his impervious armor of indifference.
4. The species was able to survive in harsh conditions due to its impervious skin that protected it from environmental threats.
5. The young child seemed impervious to the cold, playing happily in the snow without any sign of discomfort.