Def.1 To express disbelief in something someone has just said.
Tom; "Did you hear that jamie gave me crabs."
Eddie; "Get the fuck outta here!!"
Often heard in movies where the characters are Italian Americans living in New York.
It simply means that you don't believe what someone else said.
Henry Hill: There it is, you see that Mike? You see that Helicopter? See it right there, right infront of us there? I think it's been following me all morning.
Mikey: Get the fuck outta here! What are you, nuts?
An interjection of displeasure.
A fella surprise his wife while she is doing it with the mailman, the gardener or his best friend. He will yell to them: " Get the fuck outta here!" (an asking from his part to them to take the fucking act out of his bedroom and out of his sight) and will slam the door closed after they move out and do it outside.
The interjection is also known to be a good palliative to heart attack when seeing unexpected unpleasant thing.
However it didn't work for OBL. He used it as a spell against the team six guys who got in his basement: " Get the fuck outta here!" but he get shoot anyway. The team six guys appeared to be deaf dumb both.