1) Bigness 2) Enormity 3) Enormousness 4) French word used in English 5) Grandness 6) Greatness 7) Hugeness 8) Immenseness 9) Largeness 10) Sizeableness 11) Vastness Found on https://www.crosswordclues.com/clue/immensity
Im·men'si·ty noun ; plural Immensities . [ Latin immensitas : confer French immensité .] The state or quality of being immense; inlimited or immeasurable extension; infinity; vastness in extent or bulk; greatness. « Lost in the wilds of vast immensity .... Found on http://www.encyclo.co.uk/webster/I/13