Peg away
I believe the answer is:
toil
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">peg away</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for toil that I've seen before include "Work extremely hard" , "Hard physical work" , "Work incessantly" , "Work hard, labour" , "Drudgery" .)