A structural deficit refers to a long-term imbalance between government spending and revenue that is not due to temporary economic factors. It occurs when government expenditure consistently exceeds its income, leading to an accumulation of debt over time. This can result from various causes such as excessive spending on public programs or tax cuts that reduce the amount of revenue collected by the government. A structural deficit is typically addressed through a combination of spending reductions and revenue increases rather than solely through budget cuts, which may only provide temporary relief.