The Collaborative International Dictionary of English v.0.48:

Unallied \Un`al*lied"\ ([u^]n`[a^]l*l[imac]d"), a.
   Not allied; having no ally; having no connection or relation;
   as, unallied species or genera.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

29 Moby Thesaurus words for "unallied":
   alien, apart, detached, disconnected, discrete, disjunct,
   disrelated, dissociated, exotic, extraneous, foreign,
   incommensurable, incomparable, independent, insular, irrelative,
   isolated, other, outlandish, removed, segregate, separate,
   separated, strange, unaffiliated, unassociated, unconnected,
   unrelatable, unrelated