(a.) of or pertaining to infancy, or to an infant; similar to, or characteristic of, an infant; childish; as, infantile behavior.

abecedarian aboriginal antenatal autochthonous babish baby babyish beginning budding childish childlike creative doll-like dollish elemental elementary embryonic fetal formative foundational fundamental gestatory immature in arms in diapers in embryo in its infancy in nappies in swaddling clothes in the bud in the cradle inaugural inceptive inchoate inchoative incipient incunabular infant infantine initial initiative initiatory introductory inventive juvenile kittenish nascent natal neonatal newborn original parturient postnatal pregnant prenatal primal primary prime primeval primitive primogenial procreative puerile rudimental rudimentary ur