incomprehensible
inexplicable
undetermined
able
enigmatic
incalculable
incognizable
invisible
mysterious
puzzling
sealed
strange
unapparent
unapprehended
unascertained
unbeknown
uncharted
unclassified
undetected
undisclosed
undiscoverable
undiscovered
undivulged
unexplored
unexposed
unfamiliar
unfathomed
unheard
unheard-of
unidentified
uninvestigated
unknowable
unknown
unperceived
unplumbed
unrevealed
unseen
unsolved
unspied
unsuspected
untouched
untraced
untracked
virgin
abnormal
accidental
catastrophic
disturb
impending
unavoidable
unconnected
undefined
unexpected
unexplainable
unforeseen
unprecedented
unpredictable
unrelated
Refrained
abstained
arraigned
ascertained
attained
brained
campaigned
caned
chained
complained
constrained
contained
craned
deigned
detained
disdained
drained
entertained
explained
feigned
gained
grained
ingrained
maintained
maned
obtained
ordained
pained
pertained
planed
preordained
rained
refrained
regained
reigned
reined
remained
restrained
retained
retrained
self-contained
sprained
stained
strained
sustained
trained
unconstrained
unrestrained
unstained
untrained