Inflation, Deflation Recession,Reflation

Inflation:
Steady increase in price level of goods and services in an economy.
Causes
Change in money supply
Change in Disposal Income-wages
Change in Spending- Private-Business-Government
Change in Demand and Supply condition
Hoarding, Black Marketing, Corruption
Deflation 
Decrease in the general price level of goods and Services over a period of time. It is a situation where inflation is below zero percent.
Causes
Decrease in nominal prices
Purchasing power decrease
Investment
Disinflation
It is situation of slowing in the rate of price inflation over short term.
Stagflation
Generally it is assumed that inflation at a steady rate is good for the economy and it results in higher employment.  Phillips curve postulates an  inverse relationship between rates of unemployment and corresponding rates of inflation. Bur sometimes we come accross a situation of slow growth with high unemployment due to supply shock.
So It is a situation of economic stagnation with inflation of declining GDP.
Recession:
This is a situation in which the GDP of a country shows sign of decline continuously over two quarters. During this phenomenon economic activities decline. Trade and industrial activities slowdown.
Causes:
Significant fall in spending
High interest rates
Reduced consumer confidence
Reduced real wages
Reflation:
Reflation is an act of stimulating the economy by increasing the money supply by the central Bank of a Country or by Reducing taxes. 
In this situation government reduces interest rates and makes efforts to bring the economy especially the general price level back up to the long term trend following the dip in the Business Cycle.