Detachment
(Other definitions for cool that I've seen before include "Chilled" , "chic" , "Unemotional; excellent" , "Unemotional; chill" , "Neither warm nor very cold" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">detachment</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for separation that I've seen before include "Split" , "divorce" , "Break-up" , "Disunion" , "Detachment" .)