In: Economics
Colonialism is an act in which a king, queen, govt) captures someone else's territory not to merge and form one larger entity but to have it as a separate entity called a colony and be exploited for economic and commercial purposes. This is what the Britishers did to a lot of countries in the world whereas Imperialism is an act in which a king, queen, govt) captures someone else's territory to merge it with their own country forming one larger country.
Neo-colonialism is the use of economic, political, cultural, or other pressures to control or influence other countries in lieu of direct military control or indirect political control. It is the control of less-developed countries by developed countries through indirect means. It is a term where a country conquers and rules over other regions. It means exploiting the resources of the conquered country for the benefit of themselves whereas Imperialism means creating an empire, expanding into the neighbouring regions and expanding its supremacy.
Neo-colonialism is termed as building and maintaining colonies in one territory by people from another territory whereas in Imperialism a foreign government governs a territory without significant settlement.
In Neo-colonialism, we can see movement of people to the new territory and living as permanent settlers. Imperialism is just exercising power over the conquered regions either through power or indirect mechanisms of control.
The similarity or we can say both Neo-colonialism and imperialism means political and economic control of one country to another. Neo-colonialism is control over the other and Imperialism is economic and political control, either formally or informally.