Unfailingness is a term used to refer to consistency and accuracy in performance. Some antonyms that can be used to describe its opposite meaning include unreliability, inconsistency, unpredictability, volatility, and capriciousness. These terms are often associated with a lack of dependability and an inability to maintain a steady pace or perform tasks with the required level of success. Conversely, words such as reliability, dependability, consistency, and steadiness are the most appropriate antonyms for unfailingness, as they all pertain to performing tasks and achieving results with a high degree of accuracy and consistency.