Sudden burst of extravagance (7)
I believe the answer is:
splurge
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">sudden burst of extravagance</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 splurge that I've seen before include "Sudden burst of extravagance" , "Not very well" , "lashing out" , "Spend wildly" , "Orgy" .)