undetected
unnoticed
behind the curtain
behind the scenes
camouflaged
concealed
disguised
hidden
imperceptible
indiscernible
insensible
invisible
latent
out of sight
secret
sightless
submerged
unapparent
unbeheld
unbeholdable
unconsidered
undescried
undiscernible
unheeded
unmarked
unminded
unmissed
unnoted
unperceivable
unperceived
unrealized
unregarded
unremarked
unseeable
unseen
unthought-of
unviewed
unwitnessed
viewless
dormant
unable
unchallenged
unchecked
undiscovered
undisturbed
unexamined
unexplained
unexplored
unexpressed
unfelt
unharmed
unheard
unmolested
unpunished
unrecognized
unreported
unsuspected
untouched