Functional -
To me it means, working all day and at pretty much the same time most nights having a drink.
This person needs a drink pretty much every night until they black out but can get up in the morning, and go to work and pay the bills etc.
Functional -
To me means, not quite in trouble yet. Can still do things that most people see as normal. You know taking kids to basketball practice, going to work and cooking tea.
Its when you cant do these things without reminding yourself, its non functional.
JJ