Somebody who considers themself so tied to someone else that they are only there to do the other's bidding. A slave. By analogy with an actual third arm, with which the owner of the arm could hope to do so much more, but which has no independent life of its own.
Mary is trying to treat Jimmy like her third arm again. She won't even let him go out for a night with the lads.
by Fearman March 28, 2008
Get the third armmug. Oh man, I gave Mary the ol' strong arm last night, she loved it. I'm gonna go over her house again tonight to dip the wick again.
by rayjay November 5, 2004
Get the strong armmug. 
Short for Salvation Army.
by Coolio Fooly-o November 23, 2009
Get the Sal Armmug. by M0n$t3r August 18, 2014
Get the arm dartmug. The act of jiggling one's fat on the underside of the bicep area of their arm. This jiggling can also occur on the calves of their legs, Double Chin, Thigh, or stomach area.
by TheNoseSucker March 14, 2017
Get the Arm Fatmug. Legend has it, back in 1982 in a factory located in Southeastern Wisconsin, an unknown person took a shit so big it would make your asshole pucker. Unable to flush the mighty shit, it was simply left in the stall until it was discovered by factory workers. The legendary shit was said to be as thick as someones forearm and stood erect above the bowl with its tapered end bent over much resembling the head of the Loch Ness Monster. To this very day, no one knows who made it...
by BurritoSupreme83 January 7, 2020
Get the The Arm of '82mug.