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 ]