The name given to a community of Manchester United fans. Mainly used by Persian and Pakistani football fans (that is true, not a racial slur). Sometimes said as "Republic of Mancunistan". A person belonging to this community is a 'Mancunistani'.
Person 1: He's a citizen of the republic of mancunistan.
Person 2: Oh, so he's a Mancunistani?
Person 1: Yeah.