To stop receiving emails from specific people, you can block their email addresses. Blocking an email address means that any messages they send to you won’t reach your Inbox anymore as they will go straight to your Junk Email folder.
Here’s how you can block any sender in the Outlook desktop and web apps.
Blocking Senders in the Outlook Desktop App
- In the “Delete” group under the “Home” tab, select the Junk icon.
Click on the Junk icon. - Choose Junk Email Options from the drop-down menu.
Click on Junk Email Options. - Navigate to the Blocked Senders tab.
Select Blocked Senders. - Select the Add button to the right of the window.
Click on the Add button. - Enter the email address you want to block. Then, click OK.
Type the email in the text field. Then, click on OK. - Choose Apply. Then, hit OK.
Select Apply. Then, click on OK.
Blocking Senders in the Outlook Web App
- Sign in to outlook.com and select the Settings icon on the top-right of the page.
Click on the gear icon. - Go to View all Outlook settings.
Click on View all Outlook settings. - Navigate to the Junk email tab.
Go to Junk email. - Under “Blocked senders and domains,” select the + Add button.
Click on +Add. - Type the email address you want to block. Hit your keyboard’s Enter key to add it to the list. Then, hit Save.
Type the email address—press Enter. 
Click on Save.