Use the word incredible when you want to express that something is astonishingly good or extremely impressive. It is a powerful adjective to highlight the exceptional nature of events, places, things, or abilities. Incredible is ideal for emphasizing the positive aspects that stand out due to their rarity or quality.

The word incredulous is used to describe the reaction of someone who is skeptical or finds it difficult to believe something. It implies a sense of doubt or disbelief in the attitude or tone of the individual. The term is often used in situations where the truth or reality of a statement or event is being questioned by an individual.

In summary, incredible and incredulous have distinct meanings and uses. Incredible is an adjective that amplifies the extraordinary nature of something, often invoking a sense of wonder and approval. On the other hand, incredulous pertains to a person's reaction of disbelief or skepticism towards a particular statement, event, or idea. While incredible is about the object being described, incredulous centers on the observer's perspective and their doubt about the credibility of what they are presented with.