This is taken from an excellent post by the disgraced Sam Kriss.
Nevertheless, it’s a definition worth preserving.

Neoliberalism is not particularly hard to define. It’s not only an ideology or a set of principles; it’s a system of practices, and an era, the one we’re living in now. What it means, over and above everything, is untrammeled ruling-class power, an end to the class-collaborationism of the post-war years and a vicious assault of the rich against the poor. This is achieved through market mechanisms, fiscal austerity and the penetration of capitalist relations into every possible facet of human life. It doesn’t mean that the role of the state vanishes — an essential precondition for neoliberalism is the destruction of working-class power and collective bargaining, and this has to be achieved, often brutally, through laws and their enforcement. There isn’t just “some role for market forces” either, but their invasion into every fathomable social situation.

Warehouse workers are electronically monitored and made to compete against each other in efficiency rankings? This is neoliberalism. The young and unemployed are encouraged to build a “personal brand” and sell themselves as a product? This is neoliberalism. If you don’t like any of this, you’re encouraged to shop ethically, reduce your personal carbon footprint and consume vaguely antagonistic culture-commodities. This is neoliberalism.

The result of all this is that our society has become atomized: we see all our relations as essentially competitive, and the people around us as rivals for scarce goods; we are all, socially and existentially, alone. Everything we do is turned into a market transaction, a form of buying and selling. And this is because the free and unfettered market isn’t a neutral system for processing human interactions, but an instrument of class power.