Can you explain what gross domestic product can indicate about a countries ecconomy?

If you compare the GDP measures over time, an increase means the economy is growing and is more likely to be in a healthy condition. When GDP rises by a reasonable amount, 2 - 5% per year for a mature country, it allows for low unemployment and an increasing standard of living if other economic conditions are also favorable and the political system can deliver rational fiscal policies.

If GDP is falling the country is in a recession or depression. These are not good, although periodic recessions are common and to be expected.