Can you add an S to an incorrect word if that word was not challenged?
The word QUAF* is played (it is incorrect as the correct spelling has two Fs). The word is not challenged. Later my opponent, who did not challenge the misspelling, adds an S to QUAF making it QUAFS.
I challenge and my opponent says that since the misspelled word was accepted then you can use it as a correct word and accept it with an S (since QUAFFS is a real word)...??
Each and every word played during a game of Scrabble is independently challengeable. In your situation, you had every right to challenge QUAFS*, no matter what its history happened to be.
Thanks for an interesting question. I hope I've answered it.
All the best,
