Here are the steps to delete a specific keyword:
Click on the arrow button at the right corner of said keyword,
Click the "Delete keyword" button.
If you would like to delete multiple keywords in a batch:
You can filter out the ones you would like to delete,
Make sure the checkboxes at their left are checked,
Click on the 'Actions' button,
❗️ You can delete the keywords from the All Keywords view. This is a safety measure, and in most cases, the views are created based on dynamic filters. An option to delete these views or keywords within the views could cause some keywords to be permanently deleted accidentally.