COOLEST is a playable word

cool Scrabble® Dictionary

adjective
cooler, coolest
moderately cold
verb
cooled, cooling, cools
to make less warm
106 Playable Words can be made from "COOLEST"
   2-Letter Words (9 found)
   3-Letter Words (26 found)
   6-Letter Words (5 found)
   7-Letter Words (2 found)