MULLIONING is a playable word

mullion Scrabble® Dictionary

verb
mullioned, mullioning, mullions
to provide with vertical dividing strips
110 Playable Words can be made from "MULLIONING"
   2-Letter Words (15 found)
   3-Letter Words (29 found)
   5-Letter Words (13 found)
   7-Letter Words (8 found)
   8-Letter Words (1 found)
   10-Letter Words (1 found)