To the less effective writer, these two words may seem identical. Indeed, their meanings are closely related. However, more effective writers will recognize and respect the important differences.
Incredible means unbelievable. Incredulous means unbelieving. While both words are adjectives, more effective writers use incredible to describe things or events and incredulous to describe the people who can’t believe the thing that exists or the event that took place.
Consider the example sentence in the graphic above. The writer of this sentence correctly distinguishes between the related but different meanings of incredible and incredulous. The process improvements and increased profits are events, and so the writer correctly selects incredible to describe them. However, the customers are people who don’t readily believe what they see. The writer correctly uses incredulous to describe them. You can be incredulous at the incredible. But being incredible doesn’t convey the skepticism conveyed in being incredulous.
Make sure that your writing recognizes such subtle differences in language. More precise language makes for more effective writing, and that better communicates the image of yourself and your brands that you want to convey to your audience.