hellacious

adjective

hel·​la·​cious ˌhe-ˈlā-shəs 

1

: exceptionally powerful or violent

2

: remarkably good

3

: extremely difficult

4

: extraordinarily large

hellaciously adverb

Synonyms

• acute
• almighty
• blistering
• deep
• dreadful
• excruciating
• explosive
• exquisite
• fearful
• fearsome
• ferocious
• fierce
• frightful
• furious
• ghastly
• hard
• heavy
• heavy-duty
• intense
• intensive
• keen
• profound
• terrible
• vehement
• vicious
• violent

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

Just when the series appeared to begin tilting toward Indiana deep into Game 4, with a 3-1 Pacers lead a real possibility, Lu Dort's hellacious defense helped force Indiana into tough shots and Shai Gilgeous-Alexander's scoring rescued Oklahoma City. —Andrew Greif, NBC news, 18 June 2025

Fueled by their hellacious defense, the Oklahoma City Thunder toppled Nikola Jokić and the Denver Nuggets with a blowout 125-93 victory in Game 7 of the Western Conference Semifinals on Sunday. —Bryan Toporek, Forbes.com, 19 May 2025

There were several hellacious spots, but the final blow was a concerto from Priest. —Brian Mazique, Forbes.com, 25 May 2025

After a solid start, his defensive flaws and diminished reflexes left him open for a hellacious left hook from Rodriguez. —Brian Mazique, Forbes.com, 4 May 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