A father-of-three had to be arrested at his sister's wedding reception when he hurled abuse at gardai who were called to deal with a disturbance.
Denis Doyle (27) was fined €100 at Blanchardstown District Court when he admitted a public order offence.
Doyle, with an address at Castlegate Heath, Adamstown, Lucan, pleaded guilty to using threatening, abusive and insulting behaviour to cause a breach of the peace.
The incident happened at the Green Isle Hotel, Condalkin, on August 17. The court heard gardai were called after staff complained that a man was causing problems.
When the gardai arrived, Doyle was abusive, using threatening language toward them. He was arrested and taken to Clondalkin garda station.
Doyle had been at the hotel for his sister's wedding and the male who staff had complained about was his brother, barrister Jennifer Jackson said.
They were outside the hotel and security said they could not get back in.
The accused had been drinking all day and "overreacted", Ms Jackson told the court.