Oxymoron. I have so often seen it used by well-informed people to mean "a stupid remark"
that I have been guilty of using it that way. Here is a sample from one of our erudite members:
"......All of which only proves that "female intelligence" is an oxymoron....."
By accident I just ran across it in a book of words, which made it clear that it is not always
a dumb juxtaposition of qualities. For instance: Chinese sweet-sour pork. Nothing stupid about
that combination.