Mischievous trick (5)
I believe the answer is:
prank
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">mischievous trick</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for prank that I've seen before include "(Amusing) trick" , "Mischievous trick" , "April fool" , "High-spirited mischief" , "Practical joke or trick" .)