(= budget deficit) The difference between income and expenditure of the government in a year, whereby the expenditure exceeds the income. Within the EMU it has been agreed that the budget deficit must not exceed 3% of the GDP.(= budget deficit) The difference between income and expenditure of the government in a year, whereby the expenditure exceeds the income. Within the EMU it has been agreed that the budget deficit must not exceed 3% of the GDP.