1. To leave school or a course of study before completing it:
* "He dropped out of college after his first year to pursue a career in music."
* "She dropped out of high school to get married."
2. To withdraw from a group or activity:
* "He dropped out of the race after injuring his ankle."
* "She dropped out of the conversation, looking distracted."
3. To become less involved or active in something:
* "He dropped out of the social scene after his divorce."
* "The project dropped out of the public eye after funding was cut."
4. (Informal) To be unsuccessful or to fail:
* "His business dropped out after only a few months."
* "The deal dropped out at the last minute."
In essence, "dropped out" implies a sudden or unexpected departure from a situation or activity, often with a negative connotation.