in·fan·tile / ˈinfənˌtīl; ˈinfənt-il/ • adj. of or occurring among babies or very young children: infantile colic. ∎ derog. childish: infantile jokes.DERIVATIVES: in·fan·til·i·ty / ˌinfənˈtilitē/ n. (pl. -ties) .

infantile (in-făn-tyl) adj.
1. denoting conditions occurring in adults that are recognizable in childhood, e.g. poliomyelitis (i. paralysis).

2. of, relating to, or affecting infants. i. spasms (salaam attacks) a rare but serious form of epilepsy that usually begins between three and eight months of age. It is characterized by involuntary flexing movements of the arms, legs, neck, and trunk. It may be arrested by treatment with antiepileptic drugs, corticosteroids, or ACTH.