GRUMBLING is a playable word

grumble Scrabble® Dictionary

verb
grumbled, grumbling, grumbles
to mutter in discontent
112 Playable Words can be made from "GRUMBLING"
   2-Letter Words (9 found)
   5-Letter Words (10 found)
   6-Letter Words (9 found)
   7-Letter Words (4 found)
   8-Letter Words (2 found)
   9-Letter Words (1 found)