Learner's definition of DEFICIT
1 : an amount (such as an amount of money) that is less than the amount that is needed
The government is facing a deficit of $3 billion.
We will reduce the federal budget deficit.
Some economists advocate deficit spending [=spending borrowed money] to boost a slumping economy.
2 : the amount by which a person or team is behind in a game or contest 3 chiefly US : a problem that causes a decrease in some ability