The Collaborative International Dictionary of English v.0.48:
Unguessed \Unguessed\
See guessed.
Moby Thesaurus II by Grady Ward, 1.0:
26 Moby Thesaurus words for "unguessed":
arcane, cabalistic, extraordinary, impenetrable, improbable,
inscrutable, more than expected, mystic, numinous, out-of-the-way,
past expectation, sudden, unaccountable, unannounced,
unanticipated, undivined, unexpected, unforeseeable, unforeseen,
unheralded, unhoped for, unknowable, unpredictable, unpredicted,
unprepared for, without warning