Well-nigh (6)
I believe the answer is:
almost
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">well-nigh</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for almost that I've seen before include "Not totally" , "Virtually" , "Nearly, not quite" , "practically" , "As good as" .)