You can Delete a user from the Admin Panel, under User Admin.

Before deleting a user, please note:
You will no longer be able to assign/allocate anything to the deleted User.

• The User will remain as Account Manager on Contacts
• The User will be removed from Programs/Course as a Instructor/Manager
• The User’s Good News, comments, posts will remain untouched
• The User’s Contact Profile will be dissociated with the Company

Google Account

• The User’s email account will NOT be Delete in Google Apps.  You must go to the Google Admin Console and delete the user from there.  See here on what to do before deleting a Google account.

Alternative: Consider ‘Disabling’ a user by creating a User Role named ‘Disabled’ and removing all permissions. Then, assign the disabled user to this ‘Disabled’ user role.