Entrepreneur is an individual who plans and organizes a business. He is a risk taker, a leader and responsible for all the decision taken within the business.
On the other hand, Intrapreneur is an employee within an organization who thinks and acts as an entrepreneur WITHIN a specific region of the organization. An intrapreneur will also take some decision and risks but they are not usually crucial for the future of the business. In addition, in case of a failure, an intrapreneur will not be directly affected.