Hi thomazine- I'm not sure whether you sound frustrated with tabbycat09 or with all of us.
Yes, we saw your posts and referred to it later but your answer, though it looked promising, didn't at the time fit with the letters, and as far as we could see was no more correct than OBNOXIOUSNESS,
If you know an answer is definitely right because you've done the crossword then it may have helped to explain that and to explain how you knew some of tabbycat09's letters were incorrect
Egregiousness is correct as it ties in with 7a fought, 9a disembodyment, 10a salivate, 13a Jehu, 17a mountaineered? and 19a quests. Well done thomazine.