A person that didn't complete school for two reasons:
1) Their lives outside of school were so incredibly difficult that they really had no other choice
Jack lived with his mom and little sister. His mom was a very immature parent and went out and got drunk every night and would sometimes never even come home. This forced Jack to get little Sally ready for Kindergarden everyday, forcing him to constantly be late for school until he eventually had no choice but to become a drop-out to care for Sally.
Hannah, on the other hand, got a job at Pizza Hutt and felt like she was making some massive "dough" so she dropped out of high school to just work and get more money, unaware that without a diploma, Pizza Hutt's where she's gonna stay forever.