Off topic a bit, but sister-in-law lived in UK for a year. Prior to going, her huisband's company had a class on social customs and habits. It had a "translation list" and a list of what NOT to say.
"Fannie" (as in butt) was on the bad word list.
"Smartfannie" just does not do it like "smartass" LOL!
Blair boarding chopper for london.
Yes indeed--fannie in UK equals bad bad c-word here. I learned that a few years ago--thankfully.
From The Origins and Common Usage of British Swear-words
The word 'fanny' in America is, like, 'bum', mildly vulgar, meaning 'buttocks'. In the UK, however, it is rarely used in polite conversation as it would be interpreted as meaning 'vagina'.
That's quite a different meaning!