The Collaborative International Dictionary of English v.0.48:

Babyish \Ba"by*ish\, a.
   Like a baby; childish; puerile; simple. -- Ba"by*ish*ly,
   adv. -- Ba"by*ish*ness, n.
   [1913 Webster]

WordNet (r) 3.0 (2006):

babyish
    adj 1: characteristic of a baby; "babyish tears and petulance"

Moby Thesaurus II by Grady Ward, 1.0:

19 Moby Thesaurus words for "babyish":
   babish, baby, childish, childlike, doll-like, dollish, immature,
   in arms, in diapers, in nappies, in swaddling clothes,
   in the cradle, infant, infantile, infantine, kittenish, neonatal,
   newborn, puerile