Last and worst part (3,3)
I believe the answer is:
fag end
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">last and worst part</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 fag end that I've seen before include "Remnant" , "Last piece" , "Butt - something picked up out of context" , "Cigarette butt, the last part" , "Useless bit" .)