Oirish
Fake Irish. The stage or Hollywood version, all leprechauns, shillelaghs and dodgy accents, and nothing like the real thing.
Also spelt Oyrish
De pub in Boston was pure Oirish, fiddles on de walls and green beer.

Shall I translate it into posh English for you, boi?
Good morrow to you. Here it is in posh English.
The public house in Boston was thoroughly counterfeit Irish, with fiddles upon the walls and emerald ale.
Questions
What does oirish mean in Ireland?
Fake Irish. The stage or Hollywood version, all leprechauns, shillelaghs and dodgy accents, and nothing like the real thing.
How do you use oirish in a sentence?
“De pub in Boston was pure Oirish, fiddles on de walls and green beer.”
Updated
On the list: Irish slang words