unfailable

English

Etymology

From un- +‎ fail +‎ -able.

Adjective

unfailable (comparative more unfailable, superlative most unfailable)

  1. (obsolete) infallible[1]
    • c. 1652, Joseph Hall, The Mourner in Sion (sermon)
      If then we believe this unfailable word of truth, who would not be content to mourn awhile, that he may rejoice for ever?
  2. Impossible to fail
    an unfailable test

References