I wish there was a disable button, but since there’s not, just wanted to share a small suggestion for managing many forms in the Forms Tool in case this helps anyone. Since all forms still appear as “Published”, I’ve found it can become cumbersome to manage which forms are still being used and which aren’t. So whenever we “retire” a form from the site, I rename the Form with “Archive_” at the front of the name and move it to a folder I created named “Archive”.
@tMsZA To your question, no, there’s not a way to deactivate the URL unless you delete the form, which as you mentioned you do not want to do. You can edit/hide the fields and change the color and text of the Submit button, as suggested above.