CUMULUS is a playable word

cumulus Scrabble® Dictionary

noun
pl. cumuli
a type of cloud
(adjective) cumulous
18 Playable Words can be made from "CUMULUS"
   2-Letter Words (3 found)
   3-Letter Words (6 found)
   4-Letter Words (6 found)
   5-Letter Words (2 found)
   7-Letter Words (1 found)