Laugh gleefully (7)
I believe the answer is:
chortle
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">laugh gleefully</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 chortle that I've seen before include "Laugh out loud" , "Titter" , "Joyous chuckle" , "Loud gleeful chuckle" , "Noisy gleeful laugh" .)