Infallible (8)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">infallible</span>' is the definition.<br/ ><span class="explanation-format__explanation">(similar in meaning)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for foolproof that I've seen before include "incapable of going wrong" , "Not liable to failure" , "Can't be misinterpreted, even by simpleton" , "Not admitting failure" , "sure to work" .)
(Other definitions for inerrant that I've seen before include "right all the time?" , "Just like Pope" , "Infallible; art inner (anag.)" , "without fail" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">infallible</span>' is the definition.<br/ ><span class="explanation-format__explanation">(similar in meaning)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for unerring that I've seen before include "Dead-eye" , "Not liable to mistake" , "Sure" , "Deadly accurate, always on the mark" , "Infallible" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">infallible</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for sure-fire that I've seen before include "Dead cert" , "Certain to succeed - a positive conflagration?" , "Infallible" , "Certain of success" .)