It derives from the words pure sprite, in turn Pure Sprasman has a vast and broad meaning most likely to be used on the slopes or when shennanigans are happening. Thus the term Pure Sprasman is an adjective used when a full send is about to happen, a full send is completed, a sick trick is completed, or when someone does something dumb but rad.

Invented in Borat's movie. It is said, when something great happens.