SULLENER is a playable word

sullen Scrabble® Dictionary

adjective
sullener, sullenest
showing a brooding ill humor or resentment
(adverb) sullenly
97 Playable Words can be made from "SULLENER"
   2-Letter Words (9 found)
   3-Letter Words (25 found)
   6-Letter Words (7 found)
   7-Letter Words (2 found)
   8-Letter Words (1 found)