Entry 1 sense Webster, 1913 Credulousness · Cred·u·lous·ness · IPA /ˈkɹɛd͡ʒələsnəs/ 01 n. Readiness to believe on slight evidence; credulity. 1. Readiness to believe on slight evidence; credulity. “Beyond all credulity is the credulousness of atheists.” — S. Clarke.