Just because you have never seen a word doesn’t mean it is not a word. :-)
Somewhere along the line I activated an extension or plugin which tried to anticipate what I was typing and it completed words for me, often erroniusly. As a result I have disabled everything I could find including my spell checker. Now, it no longer excanges words on me. :-)
That's pretty hard to refudiate.
You must be a wizard at Scrabble.