Imagine that a country decides not to buy or sell goods to another country. This is an embargo. What is an embargo? It is when one or several countries decide to cease trade relations with another country. Sometimes this is done for political or economic reasons to force that country to change its behavior.
An embargo has a quite noticeable impact on the economy. If a country cannot sell its goods, it loses money, and its economy may weaken. For example, if Ukraine suddenly cannot sell wheat abroad due to an embargo, it will hit Ukrainian farmers and the economy as a whole. On the other hand, if the country that imposed the embargo usually buys essential goods from the targeted country, it may also suffer from this.
One well-known example of an embargo is the long-standing embargo of the United States against Cuba. The U.S. severed all trade relations with Cuba in the 1960s. This seriously affected Cuba's economy, as they could not sell their goods in the large American market.
Therefore, when you hear about an embargo, imagine it as blocking the doors to a trading supermarket between two countries. If goods are not allowed in or out, it can somehow change the lives of people in those countries.