One who is generally dumb and does not understand references to simple subjects. Usually abbreviated to F.S.
Me: Dude, Johnny just got Glenn Beck and Ed Hardy confused.
Friend: What an Flour Sack!
Me: I know! He's a total F.S.
Friend: What an Flour Sack!
Me: I know! He's a total F.S.
by DaRumblyTank February 27, 2011
Get the flour sackmug. Two guys penetrating one girls vagina and ass at the same time and their balls slap against each other
by ling69 November 9, 2013
Get the slap sacksmug. When a mans testicles become soft, sweaty, and cling to the inside of his thighs. Often occurs simultaneously with Swamp Ass
by BoogleSmith December 2, 2013
Get the Soup Sackmug. What you say when something isn't right in Smash Bros, such as the exclusion of a character you all want, the addition of stupid items or changing the Final Smash of a character (e.g. Giga Bowser not being playable.)
WTF? Ridley and Piranha Plant got in the Smash roster, but not Waluigi? I say Sack the Sak, he's being a dick
by Smith69420 January 23, 2019
Get the sack the Sakmug. by GeenaBeena January 27, 2018
Get the Turd Sackmug. by bigdaddyfatsacks January 26, 2010
Get the Sack Slackmug. A scrotum after a shave, only a while after a shave, so that it's as prickly as a porcupine. It's like stubbly chin skin wrapped around two testicles.
by Dr. Za December 19, 2008
Get the Stubble Sackmug.