Adjective: One who is completely self-absorbed and living in a false reality. This altered universe usually involves faux-cougars, beer pong, Argyle socks, and Republican Supremacy. Someone who believes they are diceroy is often known to have "man-night" and other separatist activities, reminiscent of the antebellum South.
Close female friend (or Dave) who believes that she holds a position of importance in the life of the Queen, even though she really just sleeps on various surfaces in Party Central. A sisterwife doesn't pay rent, but is domiciled in the home of the Queen Sisterwife and has no problem leaving mass amounts of garbage and refuse for the Queen to clean up. Sisterwives often take pleasure in naked spooning with the Queen Sisterwife and her random conquests, and also have no shame in belittling young Sicilian bedfellows. Whilst a sisterwife has no respect for the Queen's minions, she will often find solace in handholding with the aforementioned young men who find themselves in the lair of the Queen.
Louis, you are taking a nap and I've called you 50 times, with no response. A sisterwife would never do that. Stop having sex with tranny prostitutes.