Adjective

(er)

horrifyingly repellent; terrifying, gruesome

The photos of the killings depict a grisly scene.

Adjective

(en adjective)

Extremely bad; awful; terrible.

* There was horrendous carnage at the scene of the plane crash.

* My journey to work this morning was horrendous !

* {{quote-magazine, date=2012-03

, author=William E. Carter, Merri Sue Carter , title=The British Longitude Act Reconsidered , volume=100, issue=2, page=87 , magazine= citation , passage=But was it responsible governance to pass the Longitude Act without other efforts to protect British seamen? Or might it have been subterfuge—a disingenuous attempt to shift attention away from the realities of their life at sea. Conditions were horrendous aboard most British naval vessels at the time. Scurvy and other diseases ran rampant, killing more seamen each year than all other causes combined, including combat.}}