Hyperadult

As matters now stand, "programs" too often result in the formation of individuals whose intelligence may be hyperadult, but whose affective and moral sensibility is childish.

Source: wiktionary

It was slow enough now that I could take a good look at her — I couldn't decide her age, but there seemed to be a youthfulness to her that belied her hyperadult authority.

Source: wiktionary

Her students - children living in a hyperadult world where playground disputes were settled with 9 mms - eventually drove her out of teaching.

Source: wiktionary

I mean, most people get off on stuff that goes back to puberty or even earlier, and 'I'm so aroused' sounds so hyperadult.

Source: wiktionary