As if

[janis nihart]

My friends and I in the 1950's and sixties regularly used the term AS IF
. I always thought it was a local(southeastern Louisiana) expression.
When it came out in the 1990's I wondered if  it may have come from  a
movie in the fifties or before.  An example of how we used it would be :
Janis asked, "Did you finish your homework?"
Bonnie replied, "As if."
In other words it meant "No way!"
She also could have answered "As if I'm finished!