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1.
Can be used in a negative or positive way.
Positive-Outstanding, Totally Slammin'
Negative-Overwhelming, unbearable!
-Damn, The work today was Hellacious

+Damn, That playas booty was hellacious
by Nessa March 20, 2004
 
2.
something so wickedly awesome that you cant think of any other word to say but Hellacious
oh man that is some hellaciously good herb, good thing i gots the mother fuckin hook up in the best damn chronix in the northern H.
by herbacious October 14, 2005
 
3.
To emphasize the intensity of something. Also can be doubled-up to really intensify an object.
1. Man, that accident left a hellacious scar on your back.

2. That pig at the fair was hellaciously ginormous. (Doubled-up)

3. Dude, that's a hellacious amount of "oregano" you have there.
by *Hawaiian Baby* July 12, 2009
 
4.
extremely bad, unpleasant, or unbearable
Isnt that one song, "Fighter" by Christina Aguilara so hellacious to your ears?
by The Crack Jackal September 06, 2003
 
5.
An Adjective used to describe something horribly bad.
Did you see that dude with the mullet walk in? It was so hellacious, I can't believe he even left the house looking like that!
by Terri L. August 18, 2007
 
6.
1) referring to an article of hell
3) possessing outrageous qualities
1) This demon wing is hellacious.
2) What a hellacious day!
by Jack B. Nimble December 16, 2002
 
7.
1. a word that actually exists.

2. an extremely unpleasant thing

3. something that annoyed you because it took too long

4. a way to describe anything that didn't go your way
1. Kit: You use the word hellacious? Sweet.

2. That was a hellacious thing.

3. That wait for a sno-cone was hellacious

4. Today was a hellacious day at work.
by um... not Bridget... May 09, 2005