Hoisted by your own petard
You though you were smart, didn't you? Well, thats you totally scundered!
A scunder can be a person or a thing. It means a "nuisance". It can be found with several pronunciations. Scunner, Scundered, Scunnered, Scunnert. It is commonly used in ulster (Northern Ireland), Scotland and the North of England.
Joe is a scunder. (Joe is a pain / nuisance)
I am scundered today (I am fed up today)
This job scunders me. (This job bores /sickens / depresses me)
Derived from the word Scunt
which comes from the word cunt
Scunder has the same meaning as scunt
but changed slightly to be more socially acceptable.
(In a class room)
Girl 1: I can't believe she backstabbed me
Girl 2: I know, she's sucha scunder.
Scunder is a word used in Northern Ireland. It is usually used in the past tense 'scundered' as an adjective, although similar in sound to the Scottish 'scunnert' it has its own specific meanning. A neat little phrase sums it up, 'hoisted by your own petard' It is often a personal retort, "That's you totally scundered", perhaps by some sly plan that has backfired.
He though he was being the smart one but now it's him that's totally scundered!