A fork of Rural Dictionary
in reference to a girl who will under no circumstances cheat or even betray the trust of her boyfriend, husband, or partner.
the term is a reference to the American revolution and the Red coat loyalists, who remained on the side of the British during the period leading up to the United States independence.
Greg: Damn, Jenna is hot as shit. I bet you by the end of the night i'll have hit that.
Harvey: Unlikely, she has a boyfriend.
Greg: That didn't stop me last weekend with Laura.
Harvey: True, but Jenna's a red coat.
Greg: Fuuuuccckk