indeterminable
undeterminable
able
beyond reach
closed forever to
closed to
enigmatic
impenetrable
impervious
inaccessible
incalculable
incognizable
lost to
mysterious
out of reach
puzzling
sealed
strange
un-come-at-able
unaccessible
unapparent
unapprehended
unapproachable
unascertained
unattainable
unavailable
unbeknown
uncharted
unclassified
undisclosed
undiscovered
undivulged
unexplained
unexplored
unexposed
unfamiliar
unfathomed
ungettable
unheard
unheard-of
unidentified
uninvestigated
unknowable
unknown
unobtainable
unperceived
unplumbed
unprocurable
unreachable
unrevealed
unsecurable
unsuspected
country
dime-sized
fairy bluebird
hi-tech
inadmissible
indiscernible
logged-on
non-being
non-objective
part
roadless
self-reflexive
shutter-lag
undescribed
undogmatic
unmended
unsearchable
untrodden