An acquaintance or random person recruited informally, generally to be used as a little extra muscle.
Tom: A few guys were giving this girl trouble at a bar last night, so I told them to stop.
Dave: Did they stop?
Tom: No, they wanted a fight and there was no way I would take them, so I went outside and got a few sidewalk soldiers to help me out.

Jill: You know some guys are going to jump you at the party right?
Tomas: Don't worry, I'll get a few sidewalk soldiers to come with.
by Sidewalk Soldier January 12, 2011
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