Anticraic
A person who sucks the fun out of a room. The opposite of craic.
Don't invite yer man, he's de anticraic, he'll have us home by ten.

Shall I translate it into posh English for you, horse?
Delighted to make your acquaintance. Here it is in posh English.
Pray do not invite that gentleman. He is the very negation of merriment and will have us abed by ten.
Questions
What does anticraic mean in Ireland?
A person who sucks the fun out of a room. The opposite of craic.
How do you use anticraic in a sentence?
“Don't invite yer man, he's de anticraic, he'll have us home by ten.”
Updated
On the list: Irish slang words