OPTIMUM is a playable word

optimum Scrabble® Dictionary

noun
pl. optimums or optima
the most favorable condition for obtaining a given result
49 Playable Words can be made from "OPTIMUM"
   2-Letter Words (15 found)
   3-Letter Words (25 found)
   4-Letter Words (7 found)
   5-Letter Words (1 found)
   7-Letter Words (1 found)