How to delete or remove a MySQL/MariaDB user account on Linux or Unix

I created a MySQL / MariaDB user account using this page. Now, I have deleted my wordpress blog and I want to delete that user account including database too. How do I delete or remove a MySQL or MariaDB user account on Linux or Unix-like system using mysql command line option?

Get the Free Newsletter!

Subscribe to Developer Insider for top news, trends, & analysis