WordNet (r) 3.0 (2006):

unestablished
    adj 1: not established; "a reputation as yet unestablished"
           [ant: constituted, established]

Moby Thesaurus II by Grady Ward, 1.0:

54 Moby Thesaurus words for "unestablished":
   at issue, conditional, conditioned, contingent, dependent,
   depending, exiled, groundless, homeless, houseless, in question,
   in suspense, in the balance, inconclusive, indecisive,
   not following, not proved, open, outcast, pendent, pending,
   stateless, suspenseful, unascertained, unattested, unauthenticated,
   uncertified, unconfirmed, uncorroborated, uncounted, undecided,
   undemonstrated, undetermined, unfixed, unfounded, unharbored,
   unhoused, unplaced, unproved, unproven, unsettled, unshown,
   unsubstantiated, unsupported, unsupported by evidence, unsustained,
   untested, untold, untried, unvalidated, unverified, up for grabs,
   without basis, without grounds