Dictionary.com
Thesaurus.com
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; cf. 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.

See Examples For:

If Reilly was at times overbearing — and known for being the kind of hellacious boss who gave employees night sweats — he was also generous and a genuine bleeding heart.

From Los Angeles Times Jul. 26, 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

Army veterans who fought through hellacious battles during the Vietnam War more than 50 years ago, White House officials said Monday.

From Washington Post Jun. 27, 2022

“We could be in for a hellacious event,” he said.

From "The Hot Zone" by Richard Preston

Vocabulary.com logo
by dictionary.com

Dictionary.com's Learning Companion

Go beyond just looking up words.
Remember them forever with VocabTrainer.

Start training