"Fides" is the Latin word for "faith."
Fideists hold that there are no rational grounds for faith. They portray faith as blind obedience or a leap in the dark. Their faith is based solely on faith, not reason.
For Catholics, blind faith is a vice, not a virtue.
God created us as intelligent beings. Our powers of the intellect are part of being in the "image and likeness" of God (Gen 1:27-18). God is not offended by our thinking about what and why we believe. On the contrary, Peter tells us we should "always be ready to give an explanation [Greek: apologos] to anyone who asks you for a reason [Greek: logos--word, logic, reason, principle] for your hope" (1 Pet 3:15).