COOPER is a playable word

cooper Scrabble® Dictionary

verb
coopered, coopering, coopers
to make or mend barrels
38 Playable Words can be made from "COOPER"
   2-Letter Words (7 found)
   3-Letter Words (17 found)
   4-Letter Words (11 found)
   5-Letter Words (2 found)
   6-Letter Words (1 found)