enormity n.

late 15c., "transgression, crime; irregularity," from Old French enormité "extravagance, atrocity, heinous sin," from Latin enormitatem (nominative enormitas) "hugeness, vastness; irregularity," from enormis "irregular, huge" (see enormous). Meaning "extreme wickedness" in English attested from 1560s. The notion is of that which surpasses the endurable limits of order, right, decency. Sense of "hugeness" (1765 in English) is etymological but to prevent misunderstanding probably best avoided in favor of enormousness, though this, too, originally meant "immeasurable wickedness" (1718) and didn't start to mean "hugeness" until c. 1800.