An account deficit refers to a situation where an individual or entity owes more money than they have in their accounts. This can occur when someone spends more money than they earn, accumulates debt through loans or credit cards, or experiences unexpected expenses that deplete their savings. An account deficit is typically measured by subtracting total liabilities from total assets and represents a negative balance in one's financial records. It can have serious consequences if not managed properly, including damage to one’s credit score, legal action by creditors, and difficulty obtaining future loans or credit.