The Collaborative International Dictionary of English v.0.48:

Subconscious \Sub*con"scious\, a.
   1. Occurring without the possibility or the fact of an
      attendant consciousness; -- said of states of the soul.
      [1913 Webster]

   2. Partially conscious; feebly conscious.
      [1913 Webster]

WordNet (r) 3.0 (2006):

subconscious
    adj 1: just below the level of consciousness
    n 1: psychic activity just below the level of awareness [syn:
         subconscious mind, subconscious]