If I asked you to name or invent a word that means ‘make ambiguous’, what would it be – ambiguify? ambiguate? I’ve felt an occasional need for such a term, to say that a word or piece of syntax ambiguates the meaning in text or speech.
I mean, sure, I can say ‘makes the sense ambiguous’. But there’s no reason not to have a one-word verb. After all, we have its antonym, disambiguate: to make something unambiguous. More on that later.
Take this use of since: Since I’ve been injured, I haven’t gone running. Does it mean ‘because’ or ‘since the time that’? Is its meaning causal or temporal? Without further information, there’s no way to be sure. The choice of conjunction ambiguates the sense.