Impassible (adjective)

1. Incapable of feeling or experiencing pain, pleasure, or other emotions; not susceptible to suffering.
2. Difficult or impossible to pass through; impenetrable.

Origin:

Late 16th century: from latin impassibilis, from in- "not" + passibilis "capable of suffering".

Examples:

1. The robot was designed to be impassible to pain, allowing it to perform dangerous tasks.
2. The impassible wall was built to protect the city from invaders.
3. The impassible terrain made it difficult for the hikers to continue their journey.
4. The impassible barrier between the two countries made it hard for people to travel.
5. His impassible attitude towards criticism made him unpopular among his peers.