Deflation is the lowering of the cost of goods and services over time. It’s the opposite of inflation, which is the gradual increase of prices in the economy over time.
You may think deflation is beneficial, especially as a consumer, since purchasing power increases, allowing the same amount of money to procure more assets or services. However, it also brings disadvantages to others. Borrowers are a prime example. They’ll pay their existing debt using money worth more than they originally borrowed.
Countries are just as (if not more) wary of deflation than inflation because of the possibility of triggering an economic recession.