Yeh nor is used to describe something that has happened which somebody didn't want to happen. It is used as the last part of a sentence, usually preceded by a swear word, to emphasise the thing that has occurred is bad.
Alastair wanted to go away with the lads to benidorm. His wife put her foot down and said he couldn't go, fucking yeh nor.
by Bigalamcc April 14, 2014