not developed to the proper or desirable degree; specif., so inadequately developed economically and industrially as to have a relatively low standard of living: underdeveloped nations
See underdeveloped in American Heritage Dictionary 4
(ŭnˌdər-dĭ-vĕlˈəpt)
adjective
Not adequately or normally developed; immature: underdeveloped leaves and flowers.
Processed in too weak a developing solution, or for too short a time, or at too low a temperature to produce a normal degree of contrast. Used of film.
Having a low level of economic productivity and technological sophistication within the contemporary range of possibility; developing: underdeveloped countries.