SLOWNESS is a playable word

slowness Scrabble® Dictionary

noun
pl. slownesses
the state of being slow
107 Playable Words can be made from "SLOWNESS"
   2-Letter Words (14 found)
   3-Letter Words (27 found)
   6-Letter Words (3 found)
   7-Letter Words (3 found)
   8-Letter Words (2 found)