Meanings
The earliest usage may be traced to a primary school in Dublin, Ireland. Initially, in the 1960s, the phrase meant what it literally denoted: it was a command to get up the yard, the school yard at St. Pius X National School in Templeogue, Dublin. Older pupils appointed as wardens would shout at children to "get up the yard", away from the road.
How to pronounce "get up the yard":
AU
Get lost!
Nonsense! I don't believe you.
I disagree.