How's she cuttin'

Irish for "How's it going", which is like saying "Hi"

muck savage

Irish word... Anyone outside of the *cough* big city of Dublin is a muck savage... or Culchie

Shenanagans

Irish word for "Carry-on/Horse play"

slan

Irish word for Goodbye, but used in English sentences in Ireland...

gammy

Irish word for useless

She has a gammy leg...

paddy wagon

Irish/English word for Police Van where they load up typical gangs of drunks that are acting the eejit in public

gaa

Short form of "Gaelic Athletic Association" which is the strange irish sports... gaelic football, hurling, handball etc...