inerrable (adjective)

1. The ancient Roman aqueducts are often regarded as inerrable engineering feats of their time.

2. In the land of Elmbrook, the legendary Sword of Truth is believed to possess inerrable power.

3. The protagonist's intuition proved to be inerrable as he solved the mystery in the detective novel.

4. In this futuristic society, the highly advanced AI system is designed to have inerrable logic and decision-making abilities.