I am not sure there has to be precedence per se (though that depends on context too). I tend to think that the work speaks for itself, and any rational person can look at the text (and potentially subtext) and derive the intended meaning from it, but also possibly add additional meaning which the work itself gives room for (my example was to showcases one reason why additional meaning can exist).
In my example i'd definitely go as far and say that the meaning of said slang takes a certain level of precedence over the intent, it doesn't matter if i didn't know about it, the meaning is established already.
Would you disagree with that?