How can I disable the use of standard ligatures?

I’m using a fixed width font, and Libre Office Writer replaces some letter sequences with the standard ligatures:

fi
ff

That’s great in most cases but in the case of a fixed width font it looks terrible of course. How can I disable this?

On 5.3 and later, just add “:-liga” to the font name. For example, if you are using “Libertinus Serif” define your style to use as font

Libertinus Serif:-liga

Unfortunately, this doesn’t seem to work for Andika. Perhaps this fix only works with fonts that explicitly include such a switch? The documentation for the font doesn’t list any such option.

@khanson679 Andika is a Graphite font, not an OpenType one, so it needs different switches. BTW, I do not see ligatures on Andika.

Andika has ff/fi/fl ligatures. I think I see the problem now. This “liga” looks like some kind of standardized OpenType feature based on the MS website. Andika provides both Graphite and OpenType switches for its features, but if it was originally designed for Graphite, then I suppose that would explain why this one is missing.