immature

 
Pronunciation: /ˌɪməˈtjʊə, ˌɪməˈtjɔː/

adjective

  • not fully developed: many of the fish caught are immature
  • having or showing an emotional or intellectual development appropriate to someone younger: his immature sense of humour

Derivatives

immaturely

adverb

Origin:

mid 16th century (in the sense 'premature', referring to death): from Latin immaturus 'untimely, unripe', from in- 'not' + maturus 'ripe' (see mature)