What is a characteristic of something described as "infallible"?

Describing something as "infallible" means that it is incapable of making mistakes or being wrong; it is consistently reliable. This characteristic implies a level of perfection or dependability that assures one that outcomes will always be correct or reliable, especially in contexts like reasoning, authority, or methods. Infallibility suggests an unwavering standard, often found in discussions about moral judgments, teachings, or systems regarded as flawless.

The other options do not align with this definition. For example, being "prone to errors" juxtaposes the idea of infallibility by suggesting a likelihood of mistakes, while "subject to opinions" introduces variability and dependency on subjective beliefs, undermining the notion of certainty and reliability. Additionally, "rarely observed" implies that something does not frequently occur, which contradicts the idea of consistent reliability that infallibility embodies.