Atrocious comes from Latin atrox, atroc- ‘fierce, savage, or cruel’ + the suffix "-ious". 

According to the Oxford English Dictionary, the earliest evidence for the word "atrocious" in English dates to 1669 in the writings of Andrew Honyman.  Another source notes had an earlier date of 1604, but there was no source material to tie it to.. 

Examples of "atrocious" used in a sentence:  
"In practice, this meant all but the most atrocious offenses got mere wrist slaps." 
"The people who are committing these atrocious acts are few, but they are mainly foreigners." 
"The food here is atrocious." 
"The judge said he had committed atrocious crimes against women."
"The treatment of the prisoners by their captors is atrocious and breaks all international laws. 

3 hours ago, drpaladin said:

We more often run into atrocious with the meanings of being appalling or of terrible quality.

I agree and would add that we frequently run into atrocious with reference to behaviour, often coupled with words such as despicable and disgusting. 

Just the facts:

ATROCIOUS Definition & Meaning - Merriam-Webster

ATROCIOUS Synonyms: 198 Similar and Opposite Words | Merriam-Webster Thesaurus

38 minutes ago, drpaladin said:

 

If I had a club, I'd be tempted to name it Rocious just to hear people say they were at Rocious. And I could market it with t-shirts, hats, and signs saying 'Be At Rocious.' 

I love the idea and I would think that not being allowed to join would be so atrocious that I my response would be ferocious.