FINNIEST is a playable word

finny Scrabble® Dictionary

adjective
finnier, finniest
having or characterized by fins
97 Playable Words can be made from "FINNIEST"
   2-Letter Words (13 found)
   3-Letter Words (26 found)
   6-Letter Words (10 found)
   7-Letter Words (3 found)
   8-Letter Words (1 found)