Hard rock band from Indianapolis Indiana who released albums in 1989 and 1991. The band's crew wore backstage passes with a photo of a scantily clad feminine backside. F.A. was hence 'Fucking Ass'.
An adjective. Often used to describe a woman. Someone with a pure, friendly, and calm face. Their facial features are usually delicate and soft. A person with a sweet face isn't pretty or cute... They are beautiful.
Dan: Did you see that waitress at that coffee shop?
Tom: No. Why?
Dan: She had such a sweet face. We 'ought to get coffee there one day.
Tom: Whatever, man.
"Fanny Adams" became slang for mutton or stew and then for anything worthless – from which comes the current use of "sweet Fanny Adams" (or just "sweet F.A.") to mean "nothing at all".