When you receive a lead that you cannot qualify as an opportunity for your organisation, you can Reject it (an action also knows as marking the lead as Dead).
Rejecting the lead changes the Lead Status to Rejected/Dead - this means that it will not appear in List Views or reports for Open leads.
You can use rejected lead list views to analyse the reasons why they were not qualified.
To reject a lead:
Go to Sales > Leads and find it in your list. Use the Filter box to look for it in your current last view or the global search next to the Operate logo to search your full list of leads.
Click the company name in the lead record to access its details page.
Click Dead/Reject, in the list of options on the right.
Select the Rejection Reason and click OK.
The lead status now changes to Rejected/Dead and you can find it under the Dead Leads list view.