Shadow-Smack 

a deliberate slap against innocent bystanders in which the shadow-smacker harnesses the power of the light to cast a shadow upon ones face in a repeated slapping motion. Can also be used to diminish someone's self esteem.

Mary Beth got shadow-smacked so hard that her light bulbs blew up.

Shadow-Smack by cheeseguppy May 9, 2010

Sack Shadow

The untanned spot left on your inner thigh from where you testicles (aka ball sack, balls, sac, bag etc...) were lying when tanning or nude sun bathing.

"I kept moving my balls around while tanning to prevent sack shadow."

"I hate when I see him in briefs, his sack shadow is obvious."

Sack Shadow by muckwa July 7, 2012

shadowsack 

When the quarterback is sacked by a defensive lineman of inferior talent, due to a very talented defensive lineman that has taken up a double or triple team by the offensive line. The person credited with the sack is the shadow of a better player.

Jared Crick had many shadowsacks thanks to Ndamukong Suh taking up 3 offensive lineman at any given time in the game.

shadowsack by ThunderLS1 October 3, 2013