hellacious

horrible, awful, hellish, agonizing, difficult.

Adjective

  1. horrible, awful, hellish, agonizing, difficult.
    • Because he throws so many hellacious punches, he has the chance of knocking out any fighter on any given night. - 2007, Dan Horgan, Bringing Back Boxing: A Young Journalist's Attempt to Revive the Sweet Science, page 86:
  2. nasty, repellent.
  3. Remarkable, unbelievable, unusual.

Origin

Unclear origins; perhaps from hell + -acious

Forms

more hellacious most hellacious helatious

Derived

hellaciously hellaciousness