|1.||immature or undersized|
|2.||relating to societies in which both the surplus capital and the social organization necessary to advance are lacking|
|3.||photog (of a film, plate, or print) processed in developer for less than the required time, thus lacking in contrast|
underdeveloped un·der·de·vel·oped (ŭn'dər-dĭ-věl'əpt)
Not adequately or normally developed; immature.