Fanny Adams (30 April 1859 – 24 August 1867) was an eight-year-old English girl who was murdered by solicitor's clerk Frederick Baker in Alton, Hampshire, on 24 August 1867. The murder itself was extraordinarily brutal and caused a national outcry in the United Kingdom. Fanny was abducted by Baker and taken into a hop garden near her home, where she was brutally murdered and dismembered; some parts were never found. Further investigations suggested that two small knives were used for the murder, but it was later ruled they would have been insufficient to carry out the crime and that another weapon must have been used.

Used to express total downtime or inaction, the military, manual-trade and locker room talk phrase "sweet Fanny Adams" has been in use since at least the mid-20th century, vying with a stronger expletive. Unusually, the phrase is not a bowdlerisation; "Fanny Adams" arrived in 1860s naval slang to describe the new tinned meat which was of dubious provenance. It broadened to mean anything badly substandard, then further so as to merge with the expletive sharing its initial letters to mean nothing at all. The phrase also appears today as "sweet F.A."