- childish, infantile - indicating a lack of maturity; "childish tantrums"; "infantile behavior"
Antonym: mature (indirect, via immature)
- infantile - of or relating to infants or infancy; "infantile paralysis"
- infantile - being or befitting or characteristic of an infant; "infantile games"
Antonym: old (indirect, via young)
- infantile - being or befitting or characteristic of an infant; "infantile games"