I'm trying to understand the construction もうろうとしてる in this line from Mob Psycho 100 Episode 12:
It's translated as "he looks like he's about to pass out"。
I found a usage of もうろうとする on eow.alc.co.jp which matches the meaning "to zone out", but I'd like to understand how to deconstruct this form, if that's possible. (for example, my dictionary doesn't know the above construction, so I imagine it's a compound of some kind).
I thought this might be とする, meaning "to be about to ...", as that matches the translation, but according to jisho, that form must follow the volitional form of a verb, whereas here, it follows a と-adverb (or たる-adjective, depending how you look at it).
I've also found 必要とする in the wild which seems like a similar construct, but here 必要 is just a regular noun (and that word actually appears in the dictionary too).
Does anyone know if there is some rule that could explain this construct?