The message will be: Checked out.
Why you see the warning message: CHECKED OUT
The warning message "checked out" means that another user:
- did not correctly close the Article or other item that they were editing, or
- they are still editing the item you want to edit.
When an item is 'checked out' then no-one else may edit it until Global Checkin is performed.
It is a good idea from time to time to take a look and see if there are any checked out items.
And check them back in.
You can do this using the Global Checkin screen of your website's control panel.
How to perform Global Checkin