The Collaborative International Dictionary of English v.0.48:
Unseen \Un*seen"\, a. 1. Not seen or discovered. [1913 Webster] 2. Unskilled; inexperienced. [Obs.] --Clarendon. [1913 Webster]WordNet (r) 3.0 (2006):
unseen adj 1: not observed [syn: unobserved, unseen] n 1: a belief that there is a realm controlled by a divine spirit [syn: spiritual world, spiritual domain, unseen]