Nub (4)
I believe the answer is:
gist
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">nub</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that nub can be written as gist)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for gist that I've seen before include "Significance" , "Main points" , "The pitch on the matter" , "Essential point or meaning of, say, the matter" , "Drift" .)