KNOCKER is a playable word

knocker Scrabble® Dictionary

noun
pl. knockers
one that knocks
50 Playable Words can be made from "KNOCKER"
   2-Letter Words (9 found)
   3-Letter Words (15 found)
   4-Letter Words (18 found)
   5-Letter Words (5 found)
   6-Letter Words (2 found)
   7-Letter Words (1 found)