*Bloody 'mansplaining' - it's one of those nonsense terms coind by feminist, like it's male-only behaviour or something hmm. Just gives them the jump-start to use the word 'partriachy' a lot, and feminist-splain to us lesser 'warrior females'.
In the the real world, a 'manslapiner' is just know-it-all, who expects all around them in be in awe of their knowledge and wisdom, even if they have no idea what they are talking about. My MIL is one, as is one of my Uncles. Sometimes just nodding and smiling is the only way to deal with them - very much a 'think prick, say nothing' situation.*
Nonsense, MrsGently - a good mainsplaining term in itself! You make your own ideological biases pretty plain in your post, so I'll just say you're trying to de-gender a gendered phenomenon. I'm sure your MIL and your uncle are know-alls, but, with respect, that's purely anecdotal.
I do agree the word is annoying, but 'patriarchysplain' doesn't leap off the tongue.
DrDad, welcome to the world a lot of women live in a lot of the time. I can appreciate it is highly irritating, but if you're a woman, you get it in all kinds of contexts.