Thanks Tony, I will accept your generous capitulation, and start with a new word, as I don't win very often!
However, I have a different interpretation of the "plural s" rule. In my understanding, the word cannot win a game if the s is added to the current word to make a plural.
So I think toplines would have been legitimate. The word which would not have been legitimate is topliners.
Also, another point: I think the plural s can be played, and the previous word only wins if the plural s word cannot be followed by another word (ie, the plural s word cannot finish the game as the winner).
Opinions anyone?
Anyhow, here is our new word:
matter