Adjective, combined from "shit" and "history".
1. Used to explain a past relationship which ended badly or left a lot of bad memories.
2. Used to describe a period of time (days, months, years) that are inconsequential to the story being told.
3. Can also be used to describe a period of black out / memory loss associated with various substances
1. A: yea man... we broke up last year... I met her at the bar, and well the rest is shitory
2. B: Dude, last night was crazy.. We bought two bottles of tequila each, went to a strip club.. and the rest is shitory