The above video explains how to completely uninstall Wordpress from your cPanel.
However let us have the steps here as well if you do not wish to see the video tutorial.
Step1: Login to cPanel by visiting cpanel.yourwebsite.com
Step2: Search & click on "Wordpress" or "Wordpress Manager by Softaculous"
Step3: Click on ▽ icon available at right side of the installation
Step4: Select all 3 ticks available at the beginning and scroll down to the bottom of the page
Step5: Click on "Uninstall" or "Remove" button
Step 6: Here you go! The Wordpress has been uninstalled completed!! Enjoy
Feel free to reach us on firstname.lastname@example.org in case of any further support.