THOU is a playable word

thou Scrabble® Dictionary

verb
thoued, thouing, thous
to address as “thou” (the 2d person sing. pronoun in the nominative case)
10 Playable Words can be made from "THOU"
   2-Letter Words (5 found)
   3-Letter Words (4 found)
   4-Letter Words (1 found)