craic killer

From craic (borrowed from Irish craic, itself borrowed from Northern English crack, inherited from Middle English crak (“loud conversation, bragging talk”)) + killer.

craic killer (plural craic killers)

1. (Ireland, Northern England) Something or someone that spoils an otherwise enjoyable event.

• (something or someone who spoils an enjoyable event): dampener, buzzkill, killjoy, wet blanket, (person), party-pooper (person); see also Thesaurus:spoilsport