Use 'hard up' to express significant financial stress, suggesting difficulty in meeting basic needs. Ever since the factory closed, people in the town have been really hard up.
Pro Tip 2/3
Temporary State
'Hard up' often implies a temporary situation, not a permanent financial status. I'm a bit hard up until my next paycheck, but I'll be fine after that.
Pro Tip 3/3
Informal Usage
The term 'hard up' is casual and might be inappropriate in formal financial discussions. Don't tell the bank manager we're hard up; explain our cash flow situation professionally.