1) Expletive. 2) Office buzzword for "fucked in the ass" 3) Bad news. 4) I'm screwed. Used when you can't state the obvious around parents, cops, teachers, impressionable youth, co-workers or bosses.
See also -
- "Fuck, where are my keys?" or "f to the a, where are my keys?"
- "I got a ticket." "that's fucked up!" or "I got a ticket." "f that in the a".
f in the a literally, a sex act.
I can't call her back because my battery's dead. Basically, we're effed in the a.