A layer's heading -- NAME in this example.
You can behead it by clicking on the heading twice (no double-click).
Then clicking the delete key. Click somewhere else in your table of contents and you get this:
What happens if you want it back? (I saw this posted on a list serve and thought this is a good tip to post on my blog.) It's quite easy, but sorta hidden.
Open the Symbology properties for the layer.
Select (highlight) all the symbols you want to 'head'. Right click and choose Move to Heading > New Heading...
Enter your new header name, NAME, shown below.
Click OK. With the result, you now have your heading back.
And it shows in your table of contents when you save the changes.
Remember, you can change the heading to anything you want either in the Properties or in the table of contents.