UNHAPPENED is a playable word

unhappen Scrabble® Dictionary

verb
unhappened, unhappening, unhappens
to become as though never having happened
128 Playable Words can be made from "UNHAPPENED"
   2-Letter Words (19 found)
   5-Letter Words (13 found)
   7-Letter Words (1 found)
   8-Letter Words (3 found)
   10-Letter Words (1 found)