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A friend that is used as a substitute for a real girlfriend who performs the duties of the same. A friend that is used to give the appearance that you are in a relationship, but it is strictly platonic.
Alma: Wow you are going out with Geo AGAIN!
Syra: Yeah, our third date this week.
Alma: So you guys are dating?
Syra: No I am just his Girlfriend Sub.
by Sy Lopez August 05, 2008
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