Example: I want to make a word emphasize with a border around that single word.
You can easily create a border around a word. Mark the desired word. Select Format>Character....

In the tab “Borders” you can define a border.
i hope this can help.
Danke schön @Hrbrgr for correcting me. I tested with an outdated LO version while answering. Deleted my wrong answer.
Yeah, I was wondering.
Aber gern geschehen.
We in Germany say:
Ein blindes Huhn findet auch mal ein Korn. (das ist für mich gültig) 
OT @Hrbrgr - Also common: Ein blinder Gockel trinkt auch mal 'nen Korn… 
To all:
OpenOffice still can’t set a border around a text sequence within a paragraph. You have to insert a bordered frame for that purpose. But it’s a crook and if editing it’s pretty cumbersome…
