credulosity

From credulous +‎ -ity on the model of formations such as curiosity.

• (Received Pronunciation) IPA^(key): /ˌkɹɛd͡ʒəˈlɒsɪti/, /ˌkɹɛd͡ʒʊˈlɒsɪti/
• (General American) IPA^(key): /ˌkɹɛd͡ʒəˈlɑsɪti/

credulosity (uncountable)

1. (uncommon) credulity, credulousness, gullibility
   • 1873, William Thomas Thornton, “Recent Phases of Scientific Atheism”, in Old-Fashioned Ethics and Common-Sense Metaphysics: With Some of Their Applications‎, London: Macmillan and Co., page 237:

     But what adequate superlative shall we invent to express the credulity, the credulosity run mad, of those who, in a matter of scientific belief, deliberately accept such odds.

   • 1914 April, “Editorial Comment”, in Work With Boys: A Magazine of Methods‎, volume XIV, number 4, Reading, Pa.: William McCormick, page 127:

     […] here the Friendly Visitor must proceed with due caution and proper consideration of the credulosity of her interviewee— take a shower bath at the club nearly every night, with out any deadly results up to date

   • 2018 May, John Grant, “Introduction”, in Corrupted Science‎, revised and expanded edition, Tucson, AZ: See Sharp Press, →ISBN, page 6:

     […] further, since those members of the audience who perceive the lie will soon go elsewhere for their information, the “credulosity quotient” of the remaining audience tends to rise.

• This term is hardly found before the beginning of the 21st century.