How to install a thesaurus in LibreOffice?

Using the standard installation of LibreOffice you don't have to install it. It is already installed. You can right click any word choosing the entry »Synonyms«. Now you will get a list of synonyms to the selected word. If this does not work

• go to then main menu »Tool->Options«,
• choose the sub menu (on the left column) »Language Settings->Writing Aids«
• and then enable the option »OpenOffice.org new thesaurus« under the category »Writing Aids«.

That's it.

If this option is marked, but the thesaurus option in the tools>language menu is still grayed, then you have to perform this command using terminal:

sudo apt-get install openoffice.org-thesaurus-en-us

It is strange but, if you use English (UK) for your paragraph, Libreoffice does NOT use thesaurus. You check this under Tool > Options > Language Settings > Writing Aids > Modify and see that English (UK) has no thesaurus.

If you choose the English (USA) you can use the thesaurus. I think the problem is solved in this way.

It isn't that LibreOffice doesn't have the Thesaurus. It does, but for some reason it wasn't turned on when I installed mine.

Go to Tools > Options > Language Settings > Writing Aids > Options, make sure the top two items are checked: Check spelling as you type and Check grammar as you type.

After doing that I had the Thesaurus. I also had Check spelling as you type, but you can disable that in the toolbar, by clicking the ABC with the red squiggly line under it.

To use the Thesaurus, Ctrl+F7, or right-click on the word for which you want a synonym, hover over Synonyms.