If you're running a deficit, you are losing. You might be losing money or losing a game. Either way, you better make up for it.
When the government runs on a deficit, often the loss can be offset by a raise in taxes. If you have a deficit of iron in your body, you should consider eating more spinach. The word deficit comes from the Latin deficit meaning "it is wanting." A deficit is characterized by the wanting of something missing.
n the property of being an amount by which something is less than expected or required
temporary oxygen shortage in cells resulting from strenuous exercise