MULLION is a playable word

mullion Scrabble® Dictionary

verb
mullioned, mullioning, mullions
to provide with vertical dividing strips
47 Playable Words can be made from "MULLION"
   2-Letter Words (13 found)
   3-Letter Words (15 found)
   4-Letter Words (15 found)
   5-Letter Words (2 found)
   6-Letter Words (1 found)
   7-Letter Words (1 found)