As a noun, the French loanword laissez faire has two main definitions: (1) the principle that government should not control business, and (2) the wish not to control others. It translates literally to allow to act. In English, laissez faire is unhyphenated when it functions as a noun, and hyphenated when it functions as an adjective (e.g., laissez-faire policies). In practice, though, many publications ignore this distinction and hyphenate the term no matter how it functions.
Laissez faire is well established in English and hence does not need to be italicized in normal use.
Laisser faire is a variant spelling that appears occasionally, especially in British publications. It means the same as laissez faire.
He was so laissez-faire that a half million dollars in taxes slipped through the cracks. [Forbes]
On the contrary, Paul’s anti-statism harks back to a pre-Cold War GOP that was isolationist and laissez-faire in its outlook. [Telegraph]
Laissez-faire, far from being alien to the Canadian scene, was actually the predominant philosophy for most of the country’s first century. [Montreal Gazette]
Here, our currency is not controlled by officials. We have a laissez-faire approach. [New Zealand Herald]