RETROS is a playable word

retro Scrabble® Dictionary

noun
pl. retros
a rocket on a spacecraft that produces thrust in a direction opposite to the line of flight
58 Playable Words can be made from "RETROS"
   2-Letter Words (10 found)
   3-Letter Words (18 found)
   4-Letter Words (17 found)
   5-Letter Words (8 found)
   6-Letter Words (5 found)