What is stagflation?

Stagflation can be broken down to: Stagnation plus Inflation.

Stagnation from the economy perspective means a very slow growth in the economy and high unemployment since slow growth will not open many avenues for jobs, etc.

Inflation is persistent rise in price levels.

So, Stagflation is an environment where the economy is not growing steadily. Rather, here is a very slow growth along with high unemployment and rising prices.

Reference:

(http://money.howstuffworks.com/stagflation.htm)