hellacious

adjective

hel·​la·​cious ˌhe-ˈlā-shəs 

1

: exceptionally powerful or violent

hellacious winds

2

: remarkably good

has a hellacious curve ball

3

: extremely difficult

a hellacious climb

4

: extraordinarily large

a hellacious traffic jam

hellaciously adverb

Synonyms of hellacious

• intense
• intensive
• fierce
• ferocious
• terrible
• deep
• furious
• heavy

Examples of hellacious in a Sentence

Traffic is hellacious this time of day.

the hellacious heat was more than we could bear

Recent Examples on the Web

Even against a hellacious Houston defense, the Patriots’ shortest path to victory is to ask Maye to carry them yet again. —Andrew Callahan, Boston Herald, 15 Jan. 2026

Playing a school driver who has to get a bunch of kids to safety during a hellacious, out-of-control California fire, McConaughey learned how to drive a bus, grinding gears and everything. —Brian Truitt, USA Today, 19 Sep. 2025

The film bluntly communicates the danger of football on the body and brain, with X-ray-vision scenes that show players’ skeletons bearing the impact of hellacious hits. —Andre Gee, Rolling Stone, 18 Sep. 2025

Having a baby is never an easy experience, but the sixth episode of Outlander: Blood of My Blood plunged poor Julia (Hermione Corfield) into a hellacious labor experience. —Maureen Lee Lenker, Entertainment Weekly, 6 Sep. 2025

Word History

Etymology

hell + -acious (as in audacious)

First Known Use

1929, in the meaning defined at sense 1

Rhymes for hellacious

• arenaceous
• argillaceous
• carbonaceous
• contumacious
• coriaceous
• efficacious
• farinaceous
• foliaceous
• membranaceous
• ochraceous
• olivaceous
• ostentatious