a. 1. Not improved; not made better or wiser; not advanced in knowledge, manners, or excellence. [ 1913 Webster ]
2. Not used; not employed; especially, not used or employed for a valuable purpose; as, unimproved opportunities; unimproved blessings. Cowper. [ 1913 Webster ]
3. Not tilled, cultivated, or built upon; yielding no revenue; as, unimproved land or soil. [ 1913 Webster ]
(adj) not made more desirable or valuable or profitable; especially not made ready for use or marketing, Ant. improved, Example:taxes on unimproved land are low; unimproved dirt roads
(adj) (of land) not cleared of trees and brush; in the wild or natural state, Example:a farm with 50 acres of unimproved and 68 acres of improved land; unimproved woodlands