similar to Absofuckinglutely, this compound word expresses the desire to communicate the fact that the user is extremely confident in what they are saying.
Kevin: Are you sure you want to Ahabing tonight?
Tyler: Of couse I do.
Kevin: Are you sure dude?
Tyler: Posifuckingtively!
Tyler: Of couse I do.
Kevin: Are you sure dude?
Tyler: Posifuckingtively!
by Joey Teeter December 11, 2008