DRIED
If 1 then the score is D???? because the similarity between DYING and AGING is the ING and yet the score differed negatively. So, with words with scores of zero I formed a word that can't be scored unless the D is right.
DRIED from the D or Y that can score
GREAT - 0 so the R can go in without scoring
AGING - 0 so the I can go in without scoring
RULES - 0 so the E can go in without scoring
ROUND - 0 so the D can go in without scoring
Since the D is there with letters that can't possibly score if it does score, then the score would be one. If it scores with zero then the Y in the second position of DYING is it since the other letters can't score and we know ING isn't involved in this. So with the Y missing, the score is zero and the score is
?Y???
EDIT: Man! I was late!