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Synonyms

hellacious

American  
[he-ley-shuhs] / hɛˈleɪ ʃəs /
Or hellaceous

adjective

Slang.
  1. remarkable; astonishing.

    They're raising a hellacious amount of money in taxes.

  2. formidably difficult.

    We had a hellacious time getting here in the blizzard.


hellacious British  
/ hɛˈleɪʃəs /

adjective

  1. remarkable; horrifying

  2. wonderful; excellent

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of hellacious

hell + -acious (extracted from audacious, sagacious, vivacious, etc.), perhaps with intensive or augmentative force; bodacious, splendacious

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

And what does arrive is so hellacious that it makes the Stay Puft Marshmallow Man look sweet.

From Los Angeles Times • Feb. 12, 2026

No matter which quarterback was under center, the Commanders had trouble stopping San Francisco’s hellacious front.

From Washington Times • Dec. 24, 2022

That hellacious blaze, which burned nearly 1,000,000 acres through five counties for more than three months, was the largest single wildfire in California history.

From Seattle Times • Sep. 16, 2022

The Rams dealt two 2022 draft picks to the Denver Broncos for pass rusher Von Miller, a future Hall of Famer who joins the Rams’ hellacious Super Bowl pursuit.

From Washington Post • Nov. 2, 2021

The fear that prickled Mark’s skin was like nothing he’d ever felt, even after all the hellacious things they’d experienced since that day when all went dark in the subtrans.

From "The Kill Order (Maze Runner, Book Four; Origin)" by James Dashner