infantilism

n [U] (of older children and adults) mentally and physically underdeveloped state （指大孩子和成年人）幼稚病, 幼稚型（生理和智力发育不良的状态）.

inexpressible, inexpressibly, inextinguishable, inextinguishably, inextricable, inextricably, inf, infallibility, infallible, infallibly, infamous, infamously, infamy, infancy, infant, infant prodigy, infant school, infanticide, infantile, infantile paralysis, infantry, infantryman, infatuate, infatuated, infatuation, infect, infection, infectious, infectiously, infectiousness, infelicitous, infelicity, infer, inferable, inference, inferential, inferentially, inferior, inferiority, inferiority complex,