An exclamation reflecting a high degree of success, joy, pride or exhileration for oneself or another.
(True story): When the San Francisco Giants won the game that clinched the Western Division title in 1989, live cameras were on hand when Giants' first baseman Will Clark burst into the clubhouse. Before the announcer could react, Clark zipped past the camera exclaiming "F*ckin' A!!!". The term can be correctly used after winning a hand in poker or when accepting the prize for the best entry in the local poetry contest. Or when the doctor announces that your wife has just given birth to a baby boy: "F*ckin' A!!!"