LOCKBOX is a playable word

lockbox Scrabble® Dictionary

noun
pl. lockboxes
a box that locks
30 Playable Words can be made from "LOCKBOX"
   2-Letter Words (4 found)
   3-Letter Words (11 found)
   4-Letter Words (13 found)
   5-Letter Words (1 found)
   7-Letter Words (1 found)