adult-child
UK[ˈædʌlt tʃaɪld]US[əˈdʌlt tʃaɪld]
n
An adult who exhibits immature, irresponsible, or childlike behavior.
n
An adult who is emotionally or psychologically underdeveloped.
Morpheme Breakdown
adult
child
adult
grown-up
child
young person
Etymology
The compound noun "adult-child" is a modern English formation that directly juxtaposes two contrasting Old English and Latin-derived terms to create a new conceptual meaning. "Adult" originates from the Latin adultus, meaning "grown up," which itself evolved from the verb adolescere (to grow up, nourish). "Child" has deep Germanic roots, from Old English cild, related to kin and progeny. The compound's logic is intentionally paradoxical, combining the literal state of physical maturity ("adult") with the behavioral or emotional state of immaturity ("child"). This fusion creates a powerful, self-explanatory term for a psychological or social archetype, where the historical meanings of the components are preserved but placed in a new, contradictory relationship to describe internal conflict or arrested development.
Analysis
Structure: adult (grown-up) + child (young person)
adult: From Latin adultus (grown up, mature), past participle of adolescere (to grow up). Functions as a noun modifier.
child: From Old English cild (fetus, infant, young person). Functions as the core noun.
Examples
His inability to manage finances or hold a steady job revealed him to be a classic adult-child.
The therapy focused on helping the adult-child develop emotional maturity and take responsibility.
She felt more like a parent than a partner, constantly caring for her adult-child husband.