Hello Jet,
Just how important is this person in your life? Is she a family member or other such influential person? If not, I have to wonder why you suffer her seeming superiority. Even as I write this though, several nieghbours right out of the X-Files, do come to mind that have been in my life, or the lives of others close to me. I try to follow the old addage; that good fences make for good neighbours - and just for the reason you have illuminated.
If this is just a neighbour that you happened to get too close to, before you discovered her true nature, then I would sugget that you tell her outright, that you do not subscribe to gossip, nor will you entertain any form of it in your house. That'll give you the perfect opportunity to establish a little distance. Unless I miss my mark, she simply won't be able to help herself. That's when you have to use all the assertiveness training that you ever wished you'd taken
; you have to hold your ground, and tell her that "we've discussed this before, and I'm simply not going to put-up with it any longer". Then you'll have to ask her to leave. This may not be easy the first time, or the second. You might just say that you had something else that you should do that you'd been neglecting anyway. In time, she will either stop gossiping (which I HIghly doubt), or simply find someone else to latch on to, who WILL engage in ' a little harmless gossip.'
There is never anything harmless about gossiping! When we hear people talking - or gossiping - about others, we rarely, if ever, hear someone speaking 'under their breath' so-to-speak, about anything positive about people. You never hear someone gossiping about ... how well a new family is adjusting to their new neighbourhood; how totally 'in-tune' a particular father is with his children, etc., etc., etc.. Gossip brings out the sometimes vindictive side of us, especially when we happen to become the target of gossip. It should be ignored completely, lest some reaction or comment that you make just further inflates the problem. Do not lower yourself to slithering in the dirt with the other gossipers.
Seems such simplistic advice - a little kernel that has stayed with me always - My Mama always said, that if you can't say something nice, then don't say anything at all. Something that you might convey to your nosey neighbour!
Good luck Jet - keep us informed ok?
One thousand blessings to you and yours, Jet ~J