Jackeen

n.

Heard in Waterford, Kilkenny, Mayo, Dublin, Galway and Carlow

A derogatory term for someone from Dublin, used by people from the rest of Ireland.

In use

Look at yer man in his shiny shoes, yer some jackeen biy!

Posh English

Observe that fellow in his polished footwear, you are quite the metropolitan gentleman, aren't you!

Same phrase, other counties