It means folly or stupidity.
lain:
Not if you understand the word.
For anyone wondering about what she's doing there, Tam posted a video on this site where a guy dropped an F-bomb. My son heard it because I played it not suspecting she'd be careless enough to do that. When she was notified of it she immediately apologized for the mistake and removed it from the site...well, no. She left it in play and did her level best to convince me that it was my fault. And in a way I agree with her. Just because someone makes a strong statement of their faith and just because you have every reason to believe them to be of mature years, it doesn't follow that they'll always use judgment that meets the threshold of either of those marks. We're all human and capable of making fairly dramatic mistakes on that count.
What bothered me most about it was that when apprised of the thing she responded in a way that doubled down on negating both maturity and her faith by both leaving it here and defending it. Remarkable. I don't know if the mods ever did anything about it. I don't know if she thought better of it eventually, but I have no real reason to suspect that's true.
That she's still bringing it up gives me some hope that under the blustering immaturity in evidence she really does know better and it irks her.
It should.