You searched for: “most athermic
athermic (adjective), more athermic, most athermic
1. Pertaining to a lack of a fever or with no rise of temperature: Since Pat's temperature didn't get any higher, Dr. Anderson was relieved to see that she was getting closer to the athermic condition that he was striving to achieve for her.
2. A reference to a nonexistent opening of a passage or entrance to heat or heat-rays: The athermic coating on the space shuttle proved to be successful when it re-entered the earth’s atmosphere.
3. Characterized by the absence of fever: After a worrisome night, baby Jill seemed to be athermic and now had a cool forehead and no fever.
4. Relating to being heatless: It was speculated that many of the planets in the solar system were of an athermic nature; that is, they had no natural heat.