UMBONES is a playable word

umbo Scrabble® Dictionary

noun
pl. umbos or umbones
the rounded elevation at the center of a shield
(adjective) umbonal, umbonate, umbonic
119 Playable Words can be made from "UMBONES"
   2-Letter Words (19 found)
   6-Letter Words (1 found)
   7-Letter Words (1 found)