Source : Webster's Revised Unabridged Dictionary (1913)

Aloneness \A*lone"ness\, n.
   A state of being alone, or without company; solitariness.
   [R.] --Bp. Montagu.

Source : WordNet®

aloneness
     n : a disposition toward being alone [syn: {loneliness}, {lonesomeness},
          {solitude}]