sweet Fanny Adams absolutely nothing at all. informal

☞ Fanny Adams was the youthful victim in a famous murder case in 1867, her body being mutilated and cut to pieces by the killer. With gruesome black humour, her name came to be used as a slang term for a type of tinned meat or stew recently introduced to the Royal Navy; the current meaning developed early in the 20th century. Sweet Fanny Adams is often abbreviated in speech to sweet FA, which is understood by many to be a euphemism for sweet fuck all.