Popular Scottish term for something brilliant, most commonly used to describe an action. It describes an absolute outstanding achievement of a particular action which is hard to replicate, such as a perfect free kick in football. It is also commonly combined with other Scottish terms such as Wan to add emphasis on the brilliance of that particular action or event.
"that shot was a shclem."
"that guitar solo was a wan-schlem" - not only was the guitar solo a schlem it was also worthy of wanning to.
"I wan-schlemed all over your mother's face" - I ejaculated outstandingly all over you're mother's face.