Meaning of Aunt Fanny in English:

Aunt Fanny

Pronunciation /ˌɑːnt ˈfani/ /ˌant ˈfani/

noun

informal
  • 1Used in various phrases expressing dismissive or disbelieving contradiction of what has just been said. Especially in "my Aunt Fanny!" and "tell that to my Aunt Fanny" and variants.

  • 2In similative expressions as the type of someone ignorant or incompetent, or (more generally) someone or something unknown, irrelevant, etc.

Origin

1920s; earliest use found in Joseph Patrick McEvoy (1895–1958). From aunt + the female forename Fanny, perhaps as euphemistic alteration of my arse!.