FIRTHS is a playable word

firth Scrabble® Dictionary

noun
pl. firths
an inlet of the sea
43 Playable Words can be made from "FIRTHS"
   2-Letter Words (7 found)
   3-Letter Words (11 found)
   4-Letter Words (15 found)
   5-Letter Words (7 found)
   6-Letter Words (3 found)