undefeated
indomitable
new-fledged
newly-acquired
unattempted
unchastened
unclassified
uncollected
undetected
undiscovered
unexperienced
unexplored
unfelt
unguessed-at
unimagined
unmapped
unoccupied
unpunished
unreached
unreported
unrevealed
unsubdued
untaken
untrodden