Softaculous is an app installer which makes easy for installation of applications and CMS also for uninstalling a application which you don't need. These are some easy steps which makes easy installation and uninstalling of application and CMS.
Step 1) Login to your cPanel.
Step 2)Scroll down to Software and Services section than click on Softaculous icon.
Step 3) On the right side of top navigaton bar you need to click on "All Installations" icon as shown in below screenshot.
Step 4) Now you are redricted to next page in which list of CMS that you are installed in your hosting account which are displaying on the screen.
Now scroll down and click on X icon next to CMS that you want to uninstall.
Step 5) After clicking on X icon new page will open in which different fields are displaying.
You need to tick all the fields for removing Directory, Database, Database User for removing your installed CMS in your hosting account as shown in below screenshot.