I just installed Manjaro XFCE Edition (17.0-beta3) and could not select my favourite font Terminus from any application or xfce4-terminal, checked to see if the ‘terminus-font’ package was installed and it was. Upon further reading It is to do with the freetype2 package being updated to 2.7.1 version and having an incorrect (old) name in the font config. Terminus is now called xos4 Terminus
To be able to use xos4 Terminus in your applications and terminal again do the following
sudo nano /etc/fonts/conf.avail/75-yes-terminus.conf
<patelt name="family"><string>xos4 Terminus</string></patelt>
save the file and reboot your system to be able to select and use xos4 Terminus again.
Hopefully this helps anyone else with this perplexing issue.
There is another fix here I found after posting this if you do not want to edit user config files Terminus font name fix after freetype2 update to 2.7.1-1