No it is a mumsnet term, I was on the original thread - the 'friend' in question was called Wendy by the OP and it stuck. Ah, they were simpler times back then...
Unless there's a book and I missed that bit...very possible.
Anyway, I digress...
OP, you are Wendying your friend - you've moved in with her friends and somewhere along the line you have pissed off the original friend and now she is ghosting you. Because you've taken over her friends and muscled your way in.
Classic Wendy. And you can't see it which I suppose makes it slightly better, you haven't been deliberately vindictive, but I'd love to get the 'friend's' perspective on this.
I've been Wendied - I made a few friends at a playgroup and then went out of my way to include another mum who was very shy. Then she became unshy, took over my new friends and now I'm never invited anywhere with them. But I do get the pleasure of watching their lovely, fun times on Facebook with pathetic captions like "This lot".
I actually don't care anymore but at the time it was the worst thing ever, I was a new mum and I was lonely. In the end it turns out they're really hard work, and although I made an attempt with a few of them individually they all became really competitive and, much to my embarrassment, I spent a fortune trying to keep up so I'd be invited back in.