- greatly exceeding the common size, extent, etc.; huge; immense: an enormous fortune.
- outrageous or atrocious: enormous wickedness; enormous crimes.
- unusually large in size, extent, or degree; immense; vast
- archaic extremely wicked; heinous
Meaning “extraordinary in size” is attested from 1540s; original sense of “outrageous” is more clearly preserved in enormity. Earlier in same sense was enormyous (mid-15c.). Related: Enormously.