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3.
Your balls become inert when you get the aching and sore feeling after they have been hit or after you have had a session of intense masturbation.
"Dude, I was jerking off to Stacy's mom 15 minutes ago and now my balls are inert!"
by speckd November 14, 2007
 
1.
What the balls are. (It doesn't make a bit of difference, guys.)
"The balls are inert...!" - Piccolo
Really though, inert means doing nothing.
by Yams March 05, 2007
 
2.
The state of being so engrossed in one's device (iPhone, iPad or equivalent) that one remains oblivious to all surrounding activity and communication and to the social norms that once governed them. Accordingly, the Law of iNertia states that a person engaged with his or her device will remain so engaged, regardless of any forces acting upon them to achieve a change of state. (The Law of iNertia thus operates contrary to the Law of Inertia, according to which a body at rest will remain at rest and a body in motion will continue moving with a constant velocity unless acted upon by an external non zero force.)
"Hon, did you ask Mike to take out the trash?"

"Yeah, but he was iNert. I'll try after dinner."
by FitofPeak July 27, 2014
 
4.
When somebody is asexual or frankly is not horny at all.
My girlfriend is inert, she doesn't wanna have sex.
by Shaqqas Sanafi August 18, 2008