- remarkable; astonishing: They're raising a hellacious amount of money in taxes.
- formidably difficult: We had a hellacious time getting here in the blizzard.
Origin of hellacious
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
- remarkable; horrifying
- wonderful; excellent
C20: from hell + -acious as in audacious
Word Origin and History for hellacious
Online Etymology Dictionary, © 2010 Douglas Harper