Jackie I hadn't thought of the use of "________ illiterate" to be a way of avoiding the term culture. In fact I have often seen the expression "culturally illiterate" used. To my ears, illiteracy has an even harsher tone to it than "uncultured," but then again my parents were teachers so illiteracy amounts to something very near total depravity to me. I would classify the use of illiterate in the various ways that you mentioned as simply figurative speech. Sometimes it hits the nail on the head, such as when the subject is something that is about as fundamental as literacy. For example, if a person can't perform simple arithmetic then it's reasonable to say that they are mathematically illiterate. On the other hand if a person is unfamiliar with French New Wave cinema it would be overkill to say that they are "culturally illiterate." (In other words the lack of knowledge is not really a handicap to functioning as an independent adult in society.)
Slightly on topic, an interesting word that I came across not too long ago was aliterate, meaning someone who is able to read but essentially never reads a book.
