In traditional shared hosting, if one of the websites on the server suddenly requires a lot of resources, or is somehow compromised, the other sites on the server will likely be affected by much slower load speeds, or worse. Websites hosted on a VPS are rarely affected by such occurrences because VPSes are fully isolated environments and don’t share resources in the same way.
A virtual private server (VPS) is a virtual server that the user perceives as a dedicated server even though it is installed on a physical computer running multiple operating systems.
With a VPS, you receive all the power of dedicated hosting with the ability to have your own set of services and customizable disk space. With shared hosting, you have limited administrative access and can't customize software configurations, while with a VPS you can perform any actions from your control panel.