Arseways

n.

Heard in Meath, Kilkenny, Galway, Limerick, Offaly and Sligo

Completely wrong, botched, or turned upside down in a chaotic manner.

In use

Dats arseways now, you put the front wheels on the back like!

Posh English

That is entirely the wrong way around now, you have mistakenly mounted the steering apparatus upon the rear!

Same phrase, other counties