The Collaborative International Dictionary of English v.0.48:

hideaway \hideaway\ n.
   a hiding place; usually a remote place used by outlaws.

   Syn: hideout, den.
        [WordNet 1.5]

   2. an area where one can be alone and undisturbed.

   Syn: retreat.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

hideaway
    n 1: a hiding place; usually a remote place used by outlaws
         [syn: hideout, hideaway, den]
    2: an area where you can be alone [syn: hideaway, retreat]