When someone says something so incredibly stupid that you are at a loss for words.
Person 1 "Hey, check out this article about the Flat Earth, it's what convinced me"
Person 2 "..."
Person 1 "...you ok?"
Person 2 "...wha...? Oh, yeah, I just had a moment of Stultus Aphasia, sorry."
Stultus cunt (meaning stupid cunt) is the perfect way to insult someone you're not a fan of. As only a few people know what stultus cunt means, outsiders won't think of you badly.
Person 1: Mara is a stultus cunt, I hate her so much.
Person 2: Yeah, she really is the biggest stultus cunt that exists.
12 step recovery jargon referring to someone new who talks about how great life is, now that they'resober. Usually meaning that the person is out of touch with reality.
The new guy seems pretty happy for a dude who has no job, no money and no family. He must be on a pink cloud.