West Brit, an abbreviation of West Briton, is a derogatory term for an Irish person who is perceived as Anglophilic

in matters of culture or politics. West Britain is a description of Ireland emphasising it as under British influence.

Where did the term Jackeen come from?

Jackeen is a pejorative term for someone from Dublin, Ireland. The Oxford English Dictionary defines it as a "contemptuous designation for a self-assertive worthless fellow", citing the earliest documented use from the year 1840.

Why are people from Dublin called Jackines?

The good oul Urban Dictionary says it's from when "Dubliners used to love the Queen so much" that a Jackeen is "known by the rest of us true Irish people as Jackeens."