An entrepreneur [a person who starts and runs a business] is someone who takes on financial risk to start their own business in order to make a profit [earn more money than they spend].
For example, a person who starts a bakery or a tech company is an entrepreneur. They invest their own money and time into the business and hope to make a profit from it.
Very Simple Definition:
An entrepreneur is someone who starts their own business to make money.
For example, someone who starts a lemonade stand or sells crafts online is an entrepreneur. They want to make money by selling something they created or produced.