SUDOKU is a playable word

sudoku Scrabble® Dictionary

noun
pl. sudokus
a puzzle involving the numbers 1 through 9
25 Playable Words can be made from "SUDOKU"
   2-Letter Words (6 found)
   3-Letter Words (9 found)
   4-Letter Words (7 found)
   5-Letter Words (2 found)
   6-Letter Words (1 found)