Also found in: Idioms.


1. Distasteful and repellent: hellacious smog.
2. Slang Extraordinary; remarkable: a hellacious catch of fish.

[hell + -acious (as in audacious).]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


1. remarkable; horrifying
2. wonderful; excellent
[C20: from hell + -acious as in audacious]
hellˈaciously adv
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(hɛˈleɪ ʃəs)

adj. Slang.
1. remarkable; outstanding.
2. formidable, as in severity or difficulty: a hellacious thunderstorm.
[1925–30, Amer.; hell + -acious (extracted from audacious, etc.)]
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.


[heˈleɪʃəs] ADJ (US) → infernal
Collins Spanish Dictionary - Complete and Unabridged 8th Edition 2005 © William Collins Sons & Co. Ltd. 1971, 1988 © HarperCollins Publishers 1992, 1993, 1996, 1997, 2000, 2003, 2005


adj (US inf)
(= terrible) fighting, car crashhöllisch (inf)
(= wild) partywild
(= excellent) vacationfantastisch, phantastisch
Collins German Dictionary – Complete and Unabridged 7th Edition 2005. © William Collins Sons & Co. Ltd. 1980 © HarperCollins Publishers 1991, 1997, 1999, 2004, 2005, 2007
References in periodicals archive ?
"She is an awesome teacher but she is a hellacious person for what she did," the mother said.
The idea of communicating a person's skills--a lot of time when you are looking for a good designer to hire, it is hellacious to pick someone out of the group who has the skill and knowledge you are looking for.
I've been on some hellacious deer drags in my life, but I'm not sure any rivaled dragging that buck straight uphill in 70-degree heat.
In other words, it's a hellacious mess of thorns and is my best spot for a flush every single day.
Spent a hellacious month with my oldest son in Sloan-Kettering.
But Pure Hell was the highest and most hellacious, and Cordell had never worked himself up to jump off of it, as he had the other two.
The only way in and out of the remote Afghan region was along a hellacious pass, divided by a mountain range: aptly and religiously referred to as "IED Alley."
In the next few days, I had both long airport delays and a hellacious stomach bug.
Combined with the blanketing humidity, I have a hellacious experience searching for Torreya in the Garden of Eden.
"It's basically a hellacious amount of geometry," he says.
He attributes his business longevity to "genetics, street smarts and a hellacious work ethic that I got from my mom and my grandparents."