what does the line 'principle of laissez faire ' means...?explain

Laissez faire is an economic system in which the government of a state doesn't interfere at all in the economic practices of  its citizens. It is a sort of economic freedom; traders sell goods and services, while consumers buy them, without the interference of government policies and fiscal (economic) restrictions. While it may seem advantageous, laissez faire may give rise to fraudulent trade practices, and without authorities, consumers will feel exploited by sellers.