unwilling or unable to believe something (often by habit)
incredulous - disbelieving
This is the opposite of ‘credulous’, but has its own meaning. Whereas credulous can mean somebody who is too willing to believe something because they are foolish or naive, an incredulous person often doesn’t believe something only temporarily due to shock or surprise, not a lack of intelligence.
When my wife told me that we had won the lottery, I was absolutely incredulous! I found it so hard to believe that it was true.
I reacted with incredulity to the politician’s statement. It was completely tone-deaf.
When I broke the bad news to him he just looked at me incredulously for a moment and then began to cry.