FOILS is a playable word

foil Scrabble® Dictionary

verb
foiled, foiling, foils
to prevent the success of
(adjective) foilable
23 Playable Words can be made from "FOILS"
   2-Letter Words (9 found)
   3-Letter Words (5 found)
   4-Letter Words (7 found)
   5-Letter Words (2 found)