Right click on each entry>Properties>Abbreviate name as much as you like down to nothing if you wish.

To save space you can put similar items into folders which will need a simple name.

And just because some people don't seem to know this - the Bookmarks Toolbar continues down the right side of the page, accessed via the chevrons(>> arrowheads) at the end of the bar.

• Roomy Bookmarks Toolbar: https://addons.mozilla.org/firefox/addon/roomy-bookmarks-toolbar/

I want to keep the text hidden, I just want the bookmarks toolbar to display the icons (which is just left to each text) in each bookmark. Like, customizing widths for these bookmarks to just show icons, not icons and text