MtheGM: In what Azizi refers to as "Anglo-American English" (not a term in common usage in the US), the word "rude" has the meaning she describes as well as the meaning that you describe... except that we would not refer to a bawdy song as a "rude song". We would say that it is rude to sing a bawdy song in the supermarket or at a church social, for example.

Sharon (living at the other end of Pennsylvania from Azizi's)