MASSING is a playable word

mass Scrabble® Dictionary

verb
massed, massing, masses
to assemble in a mass (a body of coherent matter)
91 Playable Words can be made from "MASSING"
   2-Letter Words (12 found)
   3-Letter Words (28 found)
   6-Letter Words (4 found)
   7-Letter Words (1 found)