The concept of imperfect competition was propounded in 1933 in England by Joan Robinson and in America by E.H. Chamberlin.
It is an important market category where the individual firms exercise their control over the price.
Definition: Imperfect competition is a competitive market situation where there are many sellers, but they are selling heterogeneous (dissimilar) goods as opposed to the perfect competitive market scenario. As the name suggests, competitive markets are imperfect in nature.
Description: Imperfect competition is the real world competition. Today some of the industries and sellers follow it to earn surplus profits. In this market scenario, the seller enjoys the luxury of influencing the price in order to earn more profits.
If a seller is selling a non-identical good in the market, then he can raise the prices and earn profits. High profits attract other sellers to enter the market and sellers, who are incurring losses, can very easily exit the market.