GRUMBLER is a playable word

grumbler Scrabble® Dictionary

noun
pl. grumblers
one that grumbles
93 Playable Words can be made from "GRUMBLER"
   2-Letter Words (8 found)
   3-Letter Words (30 found)
   6-Letter Words (7 found)
   7-Letter Words (2 found)
   8-Letter Words (1 found)