The Collaborative International Dictionary of English v.0.48:

Separate \Sep"a*rate\, p. a. [L. separatus, p. p. ]
   1. Divided from another or others; disjoined; disconnected;
      separated; -- said of things once connected.
      [1913 Webster]

            Him that was separate from his brethren. --Gen.
                                                  xlix. 26.
      [1913 Webster]

   2. Unconnected; not united or associated; distinct; -- said
      of things that have not been connected.
      [1913 Webster]

            For such an high priest became us, who is holy,
            harmless, undefiled, separate from sinnere. --Heb.
                                                  vii. 26.
      [1913 Webster]

   3. Disunited from the body; disembodied; as, a separate
      spirit; the separate state of souls.
      [1913 Webster]

   Separate estate (Law), an estate limited to a married woman
      independent of her husband.

   Separate maintenance (Law), an allowance made to a wife by
      her husband under deed of separation.
      [1913 Webster] -- Sep"a*rate*ly, adv. --
      Sep"a*rate*ness, n.
      [1913 Webster]

WordNet (r) 3.0 (2006):

separateness
    n 1: the state of being several and distinct [syn:
         discreteness, distinctness, separateness,
         severalty]
    2: political independence; "seeking complete political
       separateness for Taiwan"
    3: the quality of being not alike; being distinct or different
       from that otherwise experienced or known [syn: otherness,
       distinctness, separateness]

Moby Thesaurus II by Grady Ward, 1.0:

101 Moby Thesaurus words for "separateness":
   alienation, aloneness, aloofness, anarchy, apartheid, celibacy,
   chaos, confusion, contrariety, contrast, departure, detachment,
   deviation, difference, diffusion, disaccord, disaccordance,
   disagreement, disassociation, disconformity, discongruity,
   disconnection, discontinuity, discordance, discrepancy,
   discreteness, disjunction, disjuncture, dislocation, disorder,
   disparity, dispersal, dispersion, dissent, dissimilarity,
   dissociation, dissolution, dissonance, distinction, distinctness,
   divergence, divergency, diversity, entropy, far cry, heterogeneity,
   immateriality, impertinence, inaccordance, inapplicability,
   inappositeness, incoherence, incompatibility, incongruity,
   inconnection, inconsequence, inconsistency, inconsonance,
   independence, inequality, inharmoniousness, inharmony,
   irreconcilability, irrelation, irrelevance, isolation,
   keeping apart, loneliness, loneness, lonesomeness, mixture,
   moving apart, nonadhesion, noncohesion, nonconformity, odds,
   opposition, otherness, privacy, scattering, seclusion, separation,
   separatism, sequestration, single blessedness, solitariness,
   solitude, splendid isolation, unadherence, unadhesiveness,
   unconformity, unconnectedness, unlikeness, unorthodoxy,
   unrelatedness, untenacity, variance, variation, variegation,
   variety, withdrawal