RIBBIEST is a playable word

ribby Scrabble® Dictionary

adjective
ribbier, ribbiest
marked by prominent ribs (curved bony rods in the body)
93 Playable Words can be made from "RIBBIEST"
   2-Letter Words (11 found)
   3-Letter Words (25 found)
   6-Letter Words (8 found)
   7-Letter Words (3 found)
   8-Letter Words (1 found)