To be honest, the slang “1140” is not a very famous term. Researching about it was very difficult due to a lack of references. The best thing we got comes from the rapper Pill. He used it in his mixtape to reference overdosing and drugs.
When used, the term “1140” might refer to any drug and the potential overdosing that comes with doing too much. You might hear someone use it like this:
“Many members of the 27 Club die because of 1140.”
“If you are doing 1140, you better get yourself checked into rehab.”
As we have said, this slang is rarely used nowadays and has fallen into obscurity.