unfailable
adjUS, UK /ˌʌnˈfeɪləbl̩/
Etymology From un- + fail + -able.
1
Impossible to fail.
- an unfailable test
2
Obsolete Infallible.
- If then we believe this unfailable word of truth, who would not be content to mourn awhile, that he may rejoice for ever?c. 1652, Joseph Hall, The Mourner in Sion (sermon)
- Related terms
- unfailing, unflagging