An excessive amount (3,4)
I believe the answer is:
too much
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">an excessive amount</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 too much that I've seen before include "American expression of approval" , "More than is tolerable" , "Beyond endurance" , "More than enough" , "Excessive, overwhelming" .)