Colonial, Post-Colonial & Neo-Colonial Nations

"Colonialism" is a term that critically refers to the political ideologies which legitimated the modern invasion, occupation and exploitation of inhabited lands by overwhelming outside military powers. For the local populations, it implied the forceful elimination of resistance, the imposition of alien rules, and the parasitic utilization of natural resources including manpower.
This term appeared in the context of Marxism and became a cornerstone of the discourse of resistance during the 20th century. 


It was meant to counter the positive connotations attached to the use of "colonization" -- understood as a legitimate "civilizing process" often reinforced by a religious agenda -- by calling attention to its actual economic motivations and denouncing its ruthless oppression.  


"Post-colonialism" loosely designates a set of theoretical approaches which focus on the direct effects and aftermaths of colonization. Post-colonialism forms a composite but powerful intellectual and critical movement.


"Post-colonialism" appeared in the context of decolonization that marked the second half of the 20th century and has been appropriated by contemporary critical discourse in a wide range of domains mapped by at least half a dozen disciplines.


Indeed, on the one hand, "post-colonial" may refer to the status of a land that is no longer colonized and has regained its political independence (e.g., post-colonial India).


In this sense, "post-colonialism" will pertain to the set of features (economic, political, social, etc) which characterizes these countries and the way in which they negotiate their colonial heritage, being understood that long periods of forced dependency necessarily had a profound impact on the social and cultural fabric of these societies (the post-colonial condition).


It may also apply to the former colonizers in as much that both extended contacts with the alien societies they conquered, and the eventual loss of these profitable possessions, deeply influenced the course of their economic and cultural evolution.  


On the other hand, "post-colonialism" may designate, and denounce, the new forms of economic and cultural oppression that have succeeded modern colonialism, sometimes called "neo-colonialism".

The term tends to point out that cooperation, assistance, modernisation and the like are in fact new forms of political and cultural domination as pernicious as the former imperial colonialism or colonial imperialism were: the devaluation of autochthonous ways of life and their displacement by the ethos of dominant nations which are technologically more advanced. Obviously, these two senses are intimately linked but foreground different aspects of a single process: the cultural homogeneization of ever larger areas of the globe. 

http://www.semioticon.com/virtuals/postcol.htm