An earlier contribution (Jeez - I typed it roight dis toime, didn't I!) gave:
Growing up in the England, I was always surprised to find out that certain,to me, everyday words, would be unknown elsewhere in the country. For example, the words "mither/mider" ( meaning to bother or annoy) are common in the north of England but pretty much unknown in the south of the country.

We Irish use "moidered" in the same sense. I've seen attempts to gloss it as Gaelic in origin, but am not convinced.

Regards