If you don't want to see a certain visitor to your website you can hide it with a few simple steps
Here's what to do:
Click on a company in your lead feed. You will see below its logo that there's the option to Hide a company. Click on the hide button and select the checkbox for Hide the lead and select Hide.
Hiding a company will delete all earlier visit details and historical data regarding that company. Keep this in mind before hiding your leads.