Here are some examples:
* "The accident was a horrendous sight." (The accident was extremely unpleasant and disturbing to witness.)
* "He had a horrendous experience in the war." (His experience in the war was terrifying and traumatic.)
* "The food was absolutely horrendous." (The food was so bad that it was revolting.)
Synonyms:
* Awful
* Terrible
* Dreadful
* Frightful
* Appalling
* Horrific
* Gruesome
Antonyms:
* Wonderful
* Pleasant
* Delightful
* Beautiful