Cyclical unemployment
Cyclical, deficient-demand, or Keynesian unemployment occurs when there is not enough aggregate demand in the economy to provide jobs for everyone who wants to work. Demand for most goods and services falls, less production is needed and consequently, fewer workers are needed, wages are sticky and do not fall to meet the equilibrium level, and unemployment results. Its name is derived from the frequent ups and downs in the business cycle, but unemployment can also be persistent, such as during the Great Depression. With cyclical unemployment, the number of unemployed workers exceeds the number of job vacancies and so even if all open jobs were filled, some workers would still remain unemployed. Some associate cyclical unemployment with frictional unemployment because the factors that cause the friction are partially caused by cyclical variables. For example, a surprise decrease in the money supply may suddenly inhibit aggregate demand and thus inhibit labor demand. Keynesian economists, on the other hand, see the lack of supply of jobs as potentially resolvable by government intervention. One suggested intervention involves deficit spending to boost employment and goods demand. Another intervention involves an expansionary monetary policy to increase the supply of money, which should reduce interest rates, which, in turn, should lead to an increase in non-governmental spending. Unemployment under "full employment"
In demands based theory, it is possible to abolish cyclical unemployment by increasing the aggregate demand for products and workers.
Unemployment, according to the OECD (Organisation for Economic Co-operation and Development), is people above a specified age (usually 15)  not being in paid employment or self-employment but currently available for work during the reference period.Unemployment is measured by the unemployment rate, which is the number of people who are unemployed as a percentage of the labour force (the total number of people employed added to those unemployed).Unemployment can have many sources, such as the following:

new technologies and inventions
the status of the economy, which can be influenced by a recession
competition caused by globalization and international trade
policies of the government
regulation and marketUnemployment and the status of the economy can be influenced by a country through, for example, fiscal policy. Furthermore, the monetary authority of a country, such as the central bank, can influence the availability and cost for money through its monetary policy. In addition to theories of unemployment, a few categorisations of unemployment are used for more precisely modelling the effects of unemployment within the economic system. Some of the main types of unemployment include structural unemployment, frictional unemployment, cyclical unemployment, involuntary unemployment and classical unemployment. Structural unemployment focuses on foundational problems in the economy and inefficiencies inherent in labor markets, including a mismatch between the supply and demand of laborers with necessary skill sets. Structural arguments emphasize causes and solutions related to disruptive technologies and globalization.