RETRO 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
19 Playable Words can be made from "RETRO"
   2-Letter Words (7 found)
   3-Letter Words (8 found)
   4-Letter Words (3 found)
   5-Letter Words (1 found)