Enormous : enormity :: huge : hugeness?
Enormous : enormousness :: huge : hugeness.
Enormity = Immense scale of evil (e.g., the "enormity of the holocaust")
"Enormousness" isn't a word in common usage that I'm aware of.
If you Google "enormity," the dictionary definitions it displays before the results are: 1.the great or extreme scale, seriousness, or extent of something perceived as bad or morally wrong. "a thorough search disclosed the full enormity of the crime" 2. a grave crime or sin. "the enormities of the regime"
Merriam-Webster claims this is not the exclusive usage, and that enormity can mean "immensity" without normative implications when the size is unexpected. But the very example it cites, from Steinbeck, involves the "enormity" of a situation in which a fire was started.
That said, I agree that "enormousness" is an awkward word, which I do not use. I'm left to ponder the enormity of my own pedantry.
I don't know if I've seen "enormousness" before this thread.
When I visited Iceland, I remember a sign in English that said a cliff was insafe [sic]. `in` being a Latin morpheme, and safe being Germanic.
Most discerning usage would be that both me "very large scale", but that enormity preserves the meaning of bad at a very large scale.
That's become something of a losing battle as the synonymous usage has become an enormity.