Not difficult (4)
I believe the answer is:
easy
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">not difficult</span>' is the definition.<br/ ><span class="explanation-format__explanation">('easy' is the opposite to 'difficult')</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for easy that I've seen before include "in plentiful supply" , "Achieved without effort" , "Not challenging" , "Simply achieved" , "Simple - not fussy" .)