preteksto

This is the gift of the band, so let us say it plainly. Preteksto is not preter plus anything, and it is not pre- plus teksto. Both of those roots are live pages on this site - preter at rank 1,528, teksto at 1,174 - and either reading would produce something a reasonable person might believe: a text placed before, a thing that goes past the text. Neither is what happened. The word came from Latin praetextus in one piece, and Esperanto has no pre- prefix at all. Antaŭ- is the prefix that means before.

The true story is the one worth carrying. Latin praetexere is prae (in front) plus texere (to weave), and texere is also where teksto comes from - a text is a woven thing, which is the same metaphor as textile and texture. So the roots really are cousins, several centuries back, in Latin. What they are not is a live Esperanto seam. That distinction is the whole lesson: a shared ancestor is not a shared affix, and only one of them lets you build new words. This is the same class as inspiri - Latin arrived fused.

And the image inside it is good. A praetexta was a toga with a purple band woven across the front, and a praetextus was anything spread in front to cover what is behind it. So a pretext is not a lie exactly; it is a real thing put where the true reason should be. That is why sub la preteksto de - under the pretext of - is the standard collocation in Esperanto as in English, and why preteksti works as a verb meaning to plead something falsely. If the excuse is simply invented, mensogi is your verb; if it is a real reason standing in for the true one, this is the word.