Farty
Forty, the way it comes out in plenty of Irish accents. Fork gets the same treatment and turns into fark.
I'll be farty-five next week and I still can't manage a knife and fark.

Shall I translate it into posh English for you, head?
A thousand welcomes, as the natives say. Here it is in posh English.
I shall be forty five next week, and I remain unable to manage a knife and fork.
Questions
What does farty mean in Ireland?
Forty, the way it comes out in plenty of Irish accents. Fork gets the same treatment and turns into fark.
How do you use farty in a sentence?
“I'll be farty-five next week and I still can't manage a knife and fark.”
Updated
On the list: Irish slang words