infallibility in·fal·li·bility US/ɪnˌfæləˈbɪləti/ uncommon noun 1. the quality of never making an error Antonymsfallibility Related words Broader terms dependability Narrower terms inerrancyPapal infallibility WordNet 2.1 (Princeton University). Wiktionary (CC BY-SA). CMU Pronouncing Dictionary. WordNet 2.1 Copyright Princeton University. All rights reserved.