I'm guessing "penultimate". Non-native speakers look up the dictionary definition, while the average American knows it means "really awesome".
It seemed somewhat plausible or serious to me because "ultimate" is slang for "really cool" in India. (At least it was when I was growing up; who knows what the cool kids there say these days.) But I was puzzled because I've spent the majority of my adult life in North America, and never heard "penultimate" used that way.
> The word penultimate as a slang word seems to have worked its way into common parlance thanks to the slang use of the word ultimate. As a slang term, ultimate means cool rather than last. So the hipster logic may have concluded that if ultimate means cool, then penultimate must mean super cool.
https://minnesota.publicradio.org/radio/podcasts/grammar_gra...
I assumed the parent was making a joke that something like this would be the case. Turns out it really is. "Never underestimate the stupidity of..."