Source : Webster's Revised Unabridged Dictionary (1913)

Babyish \Ba"by*ish\, a.
   Like a baby; childish; puerile; simple. -- {Ba"by*ish*ly},
   adv. -- {Ba"by*ish*ness}, n.

Source : WordNet®

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