Yes, users can be deleted, blocked or hidden.
Based on your follow-up comments, here is what you may want to do. First you need to find the user(s) that you want to delete
1.) To find the users, you can install this plugin:
https://www.q2apro.com/plugins/usersearch
Which displays a search box on the users page that you can use to search the users by their username(s), that is if you know their username.
Also you can search the users by their email address by adding these simple lines of code to the plugin:
https://www.question2answer.org/qa/57068/how-to-search-q2a-users-by-email-or-username-as-an-admin?show=57153#c57153 (only admin will be able to search by email, registered users can only search other users by their usernames).
2.) To expand the user listing page to more than 20, go to admin→lists→ and change the length of users page to 100 (max is 200).
3) You can find new users by logging into your site and going to the users page then click on the "new users" tab.
4.) Once you know the users (either by searching through email or username or from browsing the listing page) you can go to the user's profile and click the "block user" button below the profile which will then avail the option for "Delete user".