EXTREMEST is a playable word

extreme Scrabble® Dictionary

adjective
extremer, extremest
existing in a very high degree
noun
pl. extremes
the highest degree
112 Playable Words can be made from "EXTREMEST"
   2-Letter Words (8 found)
   3-Letter Words (18 found)
   7-Letter Words (7 found)
   8-Letter Words (1 found)
   9-Letter Words (1 found)