Coolest

adjective

1. Having a slightly low temperature; mildly or pleasantly cold.
2. Allowing or suggesting heat relief.

   "Linen has made cool and breathable clothing for millennia."

3. Of a color, in the range of violet to green.

   "If you have a reddish complexion, you should mainly wear cool colors."

4. Of a person, not showing emotion; calm and in control of oneself.
5. Unenthusiastic, lukewarm, skeptical.

   "His proposals had a cool reception."