Colorado ski resort (5)
I believe the answer is:
aspen
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">colorado ski resort</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 aspen that I've seen before include "Tree, kind of poplar" , "Trembler" , "Its leaves flutter in the slightest breeze" , "winter resort" , "One trembling" .)