Not 'cunt' necessarily. Any word of derogatory status. In effect, 'Paki' is a more specific version of [insert a nasty word - you chose 'cunt'], that negates the need for a supportive expletive. 'Cunt' however, is not dependent on skin colour, and calling someone a Scot is not insulting. The two must be combined - 'Scots cunt' - to achieve what the mighty 'Paki' commands alone!