PLAIN is a playable word

plain Scrabble® Dictionary

adjective
plainer, plainest
evident
(adverb) plainly
verb
plained, plaining, plains
to complain
37 Playable Words can be made from "PLAIN"
   2-Letter Words (9 found)
   3-Letter Words (14 found)
   4-Letter Words (12 found)
   5-Letter Words (2 found)