Wildly funny (10)
I believe the answer is:
hysterical
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">wildly funny</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 hysterical that I've seen before include "Violently emotional" , "Wildly uncontrolled" , "Emotionally unstable" , "Uncontrollably laughing or crying" , "extraordinary" .)